Car Shopping (help?)

[TickleTimeTim]

So, the transmission is finally going out in my moms 2000 ford explorer with 190k miles on it. She wants a new car and her criteria are as follows:
1) AC
2) FM radio
3) Good gas mileage
With that being said I want her to have:
1) Something reliable
2) Something cheap (affordable)
3) Possibly 4 doors
It has come down to cobalts and focus' so far. She has 3500 to put down and doesn't plan to trade in the explorer cause she would only get like $500. I found a 2010 cobalt with 30k miles for 10,997. Any suggestions? What would be a good idea for her to get?

Thanks

(I'm aware the number one answer will be yaris, but what else)