I noticed that the timeline in Aliens and Aliens: Colonial Marines videogames are somewhat inconsistent, so I made a timeline with data from the movie, videogame and Aliens: Colonial Marines Technical Manual. Check it out and tell me if its OK. Some dates are maybe wrong, please clarify me that.
June 12th, 2179. Ripley is discherged from the hospital and attends the ICC inquiry about Nostromo loss and the Alien. Carter J. Burke sent the Derelict coordinates to Hadley's Hope (Date taken from Aliens: Colonial Marines Technical Manual)
June 19th, 2179. Hadley's Hope receives transmission from Burke. Al Simpson sent Russ and Ann Jorden to the site. (Simpson says its a 2 week wait for a response from Gateway. The transmission take a week from Gateway to Earth)
June 21st, 2179. The Jorden's discovers the derelict ship and Russ gets impregnated. (Lydecker says Simpson sent the Jorden's two days ago).
June 26th, 2179. Last transmission received from Hadley's Hope. (Assuming Simpson sent a transmission to Gateway about the incident asking for further instructions inmediately after Russ was facehugged.)
June 28th, 2179. Lost contact with Hadley's Hope colony is declared. Carter J. Burke want a Marine team for a search party and the USS Sulaco is sent with Ripley and Burke on board. (Two days is a reasonable time for declare that something is wrong as they have not received any transmission from the colony).
July 19th, 2179. The USS Sulaco arrives at LV-426 and sent a transmission confirming arrival. Events of Aliens. Carter Burke sent a transmission to the Bioweapons Division confirming the existence of Xenomorphs. (The film states several times the journey to LV-426 takes three weeks, and assuming the ship send transmissions every time she arrives at destination. Stasis Interrupted states that Burke sent a transmission shortly after the Hive ambush)
July 26th, 2179. Transmission confirming arrival to LV-426 received. Bioweapons Division receives Burke transmission and sent the W-Y Legato to LV-426 (again, one week journey for the transmission from LV-426 to Gateway).
July 27th, 2179. Last known transmission from the USS Sulaco received. (Assuming Ripley or the ship sent a transmission to confirm they are on the way home).
August 9th, 2179. USS 'Sulacos scheduled return, when the ship failed to get back, is declared lost. (Again, 3 week journey back to Gateway, and if they received the transmission, O'Niell Station and Gateway must assume this is the aproximate date of arrival).
August 12th, 2179. An unnamed colonel blames Michael (Bishop?) for the lost of the USS Sulaco and offer him his help for a price. Space Command at O'Niell Station detects a mass in the Zeta 2 Reticuli system, after a check, they tagged it as the lost USS Sulaco. (Date taken from Aliens: Colonial Marines Technical Manual)
August 16th, 2179. The Legato arrives at LV-426 and start breeding xenomorphs (Three week journey from Gateway to LV-426).
August 19th, 2179. The Legato received a transmission of the location of the USS Sulaco. (One week for the transmission to reach LV-426 and the Legato was in transit, so they reached destination almost the same time).
August 27th, 2179. An outbreak occurs on the Legato as it tethered to the Sulaco. Lisbeth Hutchins destroys the ship as Samwell Stone and Turk aboard the Sulaco. The EEV with Ripley, Newt, Bishop and Turk is launched towards Fiorina 161. Samwell Stone and Hicks take the service Skiff and followed it. (Events from Stasis Interrupted and Alien 3)
August 28th, 2179. The dragon start to kill the inmates in Fiorina 161. The W-Y Patna and the Service skiff from the Sulaco are on their way (Events from Stasis Interrupted and Alien 3)
August 29th, 2179. Ripley sacrifices herself killing the Dragon and the Queen embryo on Fiorina 161, denying Michael Bishop the possibility of having a Queen. Hicks and Samwell Stone are captured. (The Weyland Yutani office learns what happened to the Sulaco on September 5th, so I assume the transmission was sent a week earlier, just after the events of Alien 3 and Stasis Interrupted, the service skiff makes a two day journey from the Sulaco to Fiorina 161).
September 5th, 2179. The Weyland-Yutani Science Division office on Gateway learns of Carter Burke's death during the events at LV-426, as no data was recovered and Bioweapons division has the situation locked, a briefing is made to discuss all the events back to 2122. (Date taken from Aliens: Colonial Marines Technical Manual)
September 11th, 2179. An extraction team from Weyland Yutani Science Division are on the way to the coordinates of the Derelict ship, and start looking from there. The search party is in charge of Seiji Tanaka aboard of the Shinyo Maru.
September 14th, 2179. Samwell Stone is executed by a W-Y commando, Levi help Hicks escape and Hicks sent part of the transmission received later by the USS Sephora. (I assume the journey from Fiorina 161 back to LV-426 takes approximately 3 weeks for the Patna as the Legato take approx the same time from LV-426 to the Sulaco. Events from 'Stasis Interrupted)
September 15th, 2179. The crew of the Shinyo Maru arrives at LV-426 and discover their "Friends" of the Bioweapons Division are already at the Derelict and recovers two eggs for the Science Division. (Date taken from Aliens: Colonial Marines Technical Manual).
September 21th, 2179. Hicks transmission is received and the USS Sephora is sent to investigate. (Events of Aliens: Colonial Marines videogame, a week transmission time)
October 12th, 2179. The USS Sephora arrives at LV-426 and events of Aliens: Colonial Marines are unfolded. (Events of Aliens: Colonial Marines videogame)
Note that the time since the Sulaco was declared lost to the events in A:CM is roughly 9 weeks, but 15 weeks since the Sulaco was sent to LV-426 which makes the 17 weeks almost accurate if they are talking about the date the Sulaco was sent, not declared lost, but its my best guess to acomodate the timeline including the Technical Manual because all the sources are canon and not necesarily contradicts each other. The Technical Manual says the Bioweapons Division had locked all the information so the Science Division sent its own expedition later. Science Division team leaded by Senji Tanaka found the people from Bioweapons Division leaded by Michael Bishop Weyland and possibly the Unnamed Corporal from the Manual. The Science Division team is probably the reinforcements which arrive at the end of Stasis Interrupted, who take control of the facility and captured the Queen. If it is true, the final act of Stasis Interrupted on September 15th, the date of the Shinyo Maru arrival.