Just a couple of thoughts - if you turn off wireless for a while and Just use ethernet - then you can work on your settings etc and get things tight - also not running wireless will piss who ever it is off and yet allow you to work (all be it connected to a bit of cat 5 cable) That way your can plan your revenge.. the other thing is if you and a buddie have a copy of
kismacng
The 2 of you could then use / triangulate on the person using your mac address (you would have to catch them live) and scare the S*it out of them!
Good luck and let us know how you go!