use the child support to pay for the child's needs and save your work income. otherwise the father can argue you don't need that much child support.
it is fair to use child support to pay for half your car expenses since it is used to transport the child. it should be paying for half the child's food/breast feeding supplies, half the clothing, half the diapers, half the housing.
if you are not paying 'rent' to your parents, the child should be. if a room for rent in your area goes for $100/week, child support should be paying your parents $50/week. it would be their option to save that money as a gift for you later on to help you move into your own place.
in reality, it doesn't matter if its child support money or your paycheck paying for the car and diapers....but you need to be able to account for how the amount of the child support is used for the child..
you could make a case for the child support going to 1/4 of the security deposit, rent......
you should be covering 75% of the rent with your income....50% for you and 25% for the child...with the child support paying the other 25%