petrmaje,
yeah, thanks for the advice I already spent way too much time in this crappy onboard card. Why did they include anyways.
Igor,
good to know, that the wifi probably will be as crappy in the R1S. I will look for an stable, fast, USB wifi device now with a good reception. I hope there is one out there.
First result:
I have a spare TP-Link TL-WN722N which is has a great reception (better than all wifi routers I used) and is working rock stable as Access point with Kernel 3.4. Certainly there has to be a downside to this. n mode is unstable so I have to stick with g for the time being. External USB power supply didn't help.
At least my wife stopped complaining, which is a great step forward.
Today I ordered a RaLink RT5370 and a LogiLink WL0150. As soon as I have some results I will post them here.