Julie:
A few months ago, I was where you are.
I had just paid off my 2003 PT Cruiser (which, by the way, I love.) It's got 151K miles on it, but it gets 27 mpg. I've replaced the brakes and tires twice, water pump, timing belt and who knows what else. I was considering getting a new car this summer, but now that I'm paying about $100 a week for gas to and from work (it's 55 miles each way), the $ that I was saving by not having car payments is all going to gas, and then some.
I talked to my repair guy, and we decided since there isn't TOO much else that can break or wear out, I'll just drive it until it dies by the side of the road. For the time being, a new car is out of the question. I guess I'll just have to jump off that bridge when I come to it.