KBB trade-in is $650 for good condition LX 105K miles. Your best bet will probably be to put in a used engine (weekend job if you have a garage. Drop the coverage on the car, and you'll probably see payback within a year (or two).
You need to train your girlfriend that she can't get rid of her old car so easily.
There were so many of those made you should be able to find one in
Windeseile.