I went to auburn for undergrad for Civil but I'm not an international student, I'll try to answer to the best of my ability. In terms of living, there's a lot of different apartment complexes, prices vary depending on how close you are to campus, how many roommates, how nice of a place you want to live in. If you're smart an you find the right situation and spend the time searching i'm sure something around 300 a month or cheaper may be available. If your getting 1200 a semester I'm gonna say you'll be dipping into your money a little bit because leases are 12 months long and you'll have cost of living needs. For a car its not totally necessary to get to and from campus during class time as there is a bus system, but if you're looking to travel or do things you'll need one or make friends with someone who will.
Note: I might be understanding this wrong if your GRA position pays you on top of just waived tuition and stipend, in that case you'll have no problem