Got the car back today. Turned out that something had caused the pressure to go up even MORE. The mechanic replaced the expansion valve, did work on the drier, recharged it (naturally), and the ever popular "labor".

In the end, it set me back $300. Not the 5 or 6 hundred I was afraid of, but it still sucks a little on top of the other repairs I had done fairly recently. There were one or two folks that were interested in sending a little my way, and if you still are, I sure wouldn't say no. But make no mistake, I'm in no danger of missing a house payment or anything.

Thanks to everybody who listened to me vent and panic!