You can download the base game from this thread by KimoMaka
Game Title: Borderlands 2
Developer: Gearbox Software
Update Dumped By: Dtwpurple
Q: This isn't the latest update? Why not?
A: Borderlands 2 increased its RAM consumption when it updated to 1.08, this meant Vitamin could not dump it (yet!) as it could not run whilst Borderlands was running.
Q: How do I install this update?
A: Look at this tutorial.