Yesterday I got back my broken laptop from Acer's "Repair Center". They just exchanged the graphics card and updated the BIOS. It runs as smoothly as it did before, and the best thing is that they did not even touch the harddisk, so no data has been lost (of course I backupped the most important stuff, but this way I do not have to bother with replaying it). The next few hours it will do an "emerge -uDavN --world"...
I did not however expect the whole process to be that easy. I sent it in and got it back about a week later. Guess my next notebook will be an Acer again. 