Well does he have faster internet than you if he does use his internet since it is not illegal if not encrupted LOL!!!!  Well I am not sure I thought if your network is encrepted then it would work.But I see why maybe try changing your network name like at my brothers its named shizinit and mine shanes room so it does not connect to the other I think try changing your network name and telling you laptop to use that name and only that nam. I hope that help thanks!!!!!!!!!!!!!

Are there any firmware updates for the router? My USR unit used to do that and they released an update that helped to keep the signal from getting wiped out by interference.

This puppy needs firmware upgrade first.  Login and turn off the broadcasting feature.  I recommend static ip only with MAC filtering.  Some will argue that MAC filltering don't do this or that but I had the same problem and this fixed it.  I would also change the name of the router so he doesn't know what model you have, just don't put in a name like "yo momma" or you will be inviting hackers.  Microsoft has a artiicle on the exact problem your having.  You can try moving the router to another room or changing the channel.  If you don't want to change the channel it probably means your not comfortable with how it all works.  I recommend keep playing with it till your comfortable to how it works and then changing the channel will be easy.