i ordered a new wi-fi antenna (3€ at the bay) and it came with the mail today. I just replaced it (took a while, but worked fine following this guide). And, lucky me: My wi-fi works smooth again! I get a perfect signal in my room, far away from the wi-fi-router (haven't tried other networks yet, however, it shows me other routers as well). Conclusion: Instead of blaming the software alone, it might be worth, having a look at the hardware, too. Cheers, J.