99 chrystler sebring battery?

My 99 chrystler sebring battery dies almost everytime I shut the car off. I have to have a battery charger in my car. Sometimes the car starts right away but lately it needs the battery charger its driving me nuts! Its been to a dealership and the guy said it has electrical problems.. it also shakes a bit and feels like it doesnt idle right which i spent 500 to have that fix but whatever. i dont know how fast i am going but the other day it started working and then now its not working again.i even gota new computer and a distributor and a vaccum hose it was okay for a month or two now its doing this..i spent 1500 on the car and its just driving me nuts i dont got money to throw out on this car i hate it so much i wanna just kick it lol i like the top thats about it i cant afford a new car. My brothers a mechanic but doesn't give me much info