Albromor:
1) As much as I love the Gothic series I recommend waiting for the US release as I suspect the next patch will be ready by then. That is unless you want to spend extra time managing saves or is a Gothic fanatic. For me the current state of the game is playable but not perfect, but there are people with many more problems (I didnt have too many crashes pre-patch either).
2) I think it should run reasonably well. I got a similar setup save that I have a Gefore 6800GS gfx card (I dont know much about graphics cards and dont know how yours compare to mine). I think I read that some people have problems with Radeon cards.
Framerate is fine on medium settings and 1024x768 resolution, as long as I turn off postprocessing (HDR and bloom) and lower shadows. The reason I actually run it at lower settings than that is the ridiculous loading time, and the fact that I as an old school gamer isnt that bothered by worse graphics. And there is always a huge lag when torches are equipped as it seems like new textures are loaded into memory.
I'm checking out
www.rpgwatch.com and the official forums at
http://forum.jowood.com/forumdisplay.php?f=254 for information. The official forums arent that bad at the moment (at least not compared to the Bethesda forums), but might get worse after the US release generates more English-speaking players:p