Problems with my Chevy Lumina, Help please!

My 96 Chevy Lumina has been having problems. This has happened 3x's already in the last two days. The temperature has been so hot outside that I almost always have to use my AC any time I go out. Well, It seems like I can use it for alittle while and it's alright then like in a hour or two tops my car will surge when in idle then switch off completely. I usually hear a whistle or some type of noise like that. I always hear that noise when my car starts surging and dies. Evenetually I can get my car to start again but It takes constant turning key in ignition several times before my lumina will start. When I do get it started the way it feels to drive in my car does not feel right at all. Kind of rough while my rpms move erratically up and down and sometimes shoot up to 3 real quick when I stop and take off. I would appreciate any advice or info you have for me. I just want my car to run smoothly again.