So I took my car to my mechanic Saturday after having some really weird problems. He immediately suggested a cracked radiator, and while I was at work discovered that the cam shaft needed replaced.
He got back to me today with the cost of parts involved, about $500 (plus whatever his labor and so on would be.) However, given the nature of what needed done and the age of the car, he's not confident he won't find other significant problems once he gets in and starts changing things. As such, he doesn't really want to proceed until I've considered whether I can afford, or if the car is worth, addition costs that might arise.
However, given that I'd want a car in the 3-5k range, I'm not certain my options on simply replacing it are any better. (Cars in the 3-5k range are quite rare now due to cash for clunkers). So yeah, still deliberating.