Check out these guys:
http://www.tendit.net
I used them recently and they were AMAZING. Very cheap and got me a lot. They helped me plan everything (what drinks to serve, how much to buy, what to buy, etc), helped me setup, picked up things for me when I forgot them, reminded me to put the green beans in the oven (hahaha!), made fabulous drinks, and then even helped me clean up after the event! They charged me like $100 for the whole party and I tipped the bartender another $100--absolutely worth it! The next lowest quote I found from another place in the area was like $400-gross!