2006 Chevrolet Uplander fuel system problems

I was hit from behind on february 4, 2012 on campcreek pkwy in college park ga, because my vehicle stalled when I pressed the gas to take off from the red light, it clunks when making turns, it sounds as if something is loose on the front end, and has made these sounds since I've had it, I have had to repair the brakes frequently, the vehicle stalls when driving on the highway, the temperature gauge goes up and down, the transmission stalls.

Chevy uplander broke down in driveway. Dealer towed said it started fine for them but that the battery cells were low so they replaced the battery. They said it was ready to be picked up. On my way home from dealership the van completely shut off in the middle of a very busy highway. I managed to turn slightly but was stuck in the road for at least 10 minutes before police arrived. Dealer now thinks it is fuel pump however something is still draining battery.