Need Help 94 Grand Am won't start!

I admit that I am not that knowledgable of cars, so I will include all information that I know. I have a 94 Grand Am recently I took it into Midas to have the Heater Core fixed and they said the only thing that was wrong with it is all of the belts need to be changed, I didn't have them do it because they wanted to charge $200. About 2 months later, on July 16th I went to go start the car and it wouldn't start. It made a noise like it usually did but it wouldn't turn over and actually start, it sounded like the noise right before it actually turns on completely. Someone said it was the battery so I tried to jump it but it did nothing and everytime I turn the key the sound gets quieter and quieter now the only sound sounds like air being released from the engine when I turn the key. I am sorry but I don't know any specifics on my car type like engine type or size or any thing other than what I have explained. Could it be a belt(even with the sound slowly getting quieter and quieter each time) or is it the starter or alternator? Any suggestions would be great. Thanks
Amanda

Sounds like you ran the battery down trying to start the car. As for the car not starting, it could be many things. If you tried jumping the car and it didn't start, its probably not the starter. My suggestion is to start with the basics, air fuel and spark. It's probably getting air, turn the ignition on with a charged battery and listen for the fuel pump. It should hum for a couple of seconds. If not, then have the realy and the pump checked. If the pump hums, it might be a spark issue, have the ignition system checked.