I think everyone covered your car. Snow tires and FWD, etc.
The only thing I'll add is that assuming your commute isn't able to be reduced, you should be looking at something that maximizes your MPG. This means you may be looking at something newer and more expensive but gets better MPG than older stuff, such that it pays for itself in reduced fuel costs. Because of CAFE standards MPG is going up, yesterdays "good MPG" was 30+, and today's is 40+, with no real reduction in comfort, safety, etc.
I've noticed that Chevy Cruze Eco's are getting cheap, 10-11k, and get 42+ MPG highway. I've seen reports of 48+, especially with a "tune". 3 seasons of the year use the rock hard Eco tires, and the fourth season use snow tires and steel rims.
What about the husband's car? Seems like there's a lot of money tied up in that one.
I've attached a spreadsheet I use to make car decisions. It's pretty crude and simple but it looks at all-in costs to determine what the best choice is. Surprisingly it shows that sometimes the "cheapest" choice is not the best choice. I'd plug in all the cars you are looking at and see how it stacks up. Everyone fixates on price, but MPG, maintenance, insurance, depreciation are all important values.