Sorry to hear about your situation. It seems like there is more going on on her end, in other words she is in a 'I don't give a poop about the car' situation. Or, don't answer this, is she driving home after a night out at the wine bar with the girls?
I agree with the other posters - keep the car. Your selling prices are not very realistic, so fix the mechanical stuff, let the dust settle a bit, then go from there. Hang in there man!