2001 Ford Focus Wagon Grinding Noise

2001 Ford Focus SE Wagon 4D
2.0L Engine, 180k Miles, Automatic Transmission

My car is making a very loud griding noise while in first until it shifts to second. It's really jumpy as well, and has a LOT of trouble accelerating up hills. The problem also occurs in reverse, possibly even worse than in drive, and it's even happening in neutral when I try to coast backwards down out of my driveway.

I don't really have the money to replace the tranny, so I'm sincerely hoping that's not the problem. Before this happened (it happened all of a sudden when I got off work the other day) the car had trouble accelerating up hills. It also has a small crack in the radiator that causes me to keep filling it up with fluid to keep the car cool. I've been using water, and it's been getting extremely cold up here in Pittsburgh, so maybe that has something to do with it. I don't know anything about cars, so your guess is as good as mine.