Starting Problems

The other day I started up the car and it started fine, but when I went to put it in reverse it died. It did this a couple of times. As long as my foot was giving it gas, it would keep going. The minute I took my foot off the gas it would die. It did this for a couple of times, and after I sat there for a few minutes revving it up, it drove fine. It drove fine the rest of the day. I parked it, and the next day it did the same thing.
I need to take it in and get it reapired, but I have no clue what is going on so I want to take it to the right place. Any ideas what could cause this? At one point when it died I could not even get it to shift gears back to Nuetral to push it out of the road.