Which car for me?

So a little background on myself. I am 19 years old, a college student and I currently work at a customer support center 45 hours a week as a seasonal employee. I bring in about ~$1350 a month. I live with my grand parents, so the only real bills I pay right now are for gas, food, car insurance and pleasure. All in all I probably spend about ~$300 a month at the most. I own outright a 1997 Ford F-150 2WD (4.6L) but I am looking to sell it, because it only gets about 15mpg and I end up spending about $50 a week in gas.

SO I will be looking for a vehicle in the ~$2500 (Give or take a bit) and I am not sure what vehicle I should be looking at. I want something that:

Gets decent MPG (Better than 20MPG highway at the least)
Has a reliable drivetrain (Engine + Transmission)
Decent crash test rating (Won't be rendered useless in a small fender bender)
Has an automatic transmission (I can drive a manual just fine, however I personally prefer an automatic)
4 seats

I try to ensure all my decisions revolve around finances. So here's my current financial status:

What I owe:$4500 in student loans

What I own:$2000 in savings, $1997 Ford F-150 w/ 120K miles on it, KBB value approximately $3500

Approximate net worth:$1000



Any ideas? Thanks guys.