1996 GL 4 cyl. automatic, 84k

The problems in order of urgency (not chronology):

1. So I got my car towed. It comes off the tow truck and blocks the driveway. The tow guy puts it in park whilst we discuss payment. Then it comes time to move it. Oops, the shifter doesn't budge, and the gears don't switch. I can't push it around without screwing up the transmission.

The gears were shifting fine before the car was towed, but I've had some transmission problems before. Whenever I went on the highway going 75mph+ for 15 minutes or more, my O/D off sign would start flashing. Whenever this light is on, the car jerks forward really sharply when it switches gears. But once I turn off the engine and let it sit for a half hour or so, the problem disappears.

Does anyone know how I can get it in neutral and push it out of the way? Is this a serious transmission problem? If so, is the tow guy at all responsible?

2. The reason I had to get it towed in the first place was that my engine overheated on the highway because I ran out of antifreeze. I waited for a while, then barely made it to a gas station half a mile away (the car dying at every stop sign, then starting again), poured in some water, and got a huge explosion of steam in my face and all kinds of grinding and creaking under the hood. Since then, it doesn't even try to start. What is going on?

3. Trivial in light of the above, but what the hell. My Contour has awful handling in any kind of bad weather. I recently got brand new front and rear tires, but whenever the road is slippery or in poor condition, the whole rear of the car seems to slip and drag behind the front on the turn. I don't turn sharply, and my rear tires aren't any worse than the front. Why does this happen? Ever since I bought the car, there's been an audible grinding noise coming from the rear left side of the car. Could this be related?

I bought this car for $3700 20,000 miles ago and I couldn't possibly afford any major transmission/engine repairs. Any kind of advice would be greatly appreciated.