I'm very sorry for you. Seriously. I had a '95 VR6 Jetta and couldn't get rid of it fast enough. That engine makes great noises, but what a pile of crap. The whole car. I mean, honestly.
Anyway, you can try:
forums.vwvortex.com
Go straight to the "technical" forums, there's a 12v and a 24v (you didn't say which one yours was) forum with some decent information. Do some searches, there's a lot of info in there mixed with a bunch of junior high crap.
In your case, though, I would just plan on replacing the thermosat, thermostat housing, and 'crack pipe' that runs across the block. Buy the parts, all needed o-rings, and some coolant, and breathe easy for 2 days until something else breaks. If you replace just the thermostat, you can guarantee either the housing or the crack pipe will break within 2 months, or the coldest day of the year when you're late for work, whichever comes first.
www.parts4vws.com (not the cheapest, but better than the $tealer and awesome service)
www.germanautoparts.com (they don't have a huge selection, but prices are decent and also great service)
And of course you can always try BMA. They always can get my Mercedes stuff.