cavalier fuel problems?

i really don't know what's wrong with my cavalier.

i'm a girl and i know absolutely nothing about cars. my brother in law is the only car-guy i know, and he doesn't know either. i'm going to try and explain the best i can what it's doing...

anyway, i had been driving it one morning for less than 5 minutes, when it just turned off on me. it would start back up, but only to turn off again in 15 seconds or so. my BIL thought it was the spark plugs, but after looking at the car, he thought my fuel filter needed cleaning because he said it was really dirty. he replaced that, and it still won't start.. now it won't even start up like it did before and my battery is now dead somehow?! it doesn't even TRY to start with the new fuel filter on it. he goes back and thinks it may still be the spark plugs, so he replaces those and jumps my battery. didn't work. but now it's at least TRYING to start up.. he said it's acting like it needs gas. we put some gas in it and nothing. still trying but it won't fullyyy start up.

he thinks it has something to do with the fuel.. does anyone know??

and also, why is my battery messing up ever since he changed the fuel filter? i have to charge it every time, and the battery will die down soon after the jumper cords come off?

someone pleaseeee give me your input... i am DESPERATE! i need my car so bad right now! i would take it t a car shop, but, i'm really broke right now, and i was hoping i could at least get an idea of what's wrong with it first..