You will most likely finish the game and most, if not all the other trophies before you unlock this. The good news is, you can just let the game sit and earn you time by doing absolutely nothing. You just need to have the R2 button held down and you can leave the game idle.
Make sure you turn off the auto controller sleep options on your PS3 or else the controller will go off and pause the game and stop the time from accumulating.