You should ask your grandma if you can put off the car payments until a later time when you save up some money. And what kind of car is it? $83 a month isn't bad for a young kid, but you could save a lot of money if you just put liability on the car instead of full coverage.
There isn't much you can do with the other bills since you can't afford to cancel the contract on your phone, and you have to have the money to pay tolls to go so school, and you have to have gas.
Actually, have you figured out how much it would be to use public transportation to go to school if it's available?