Computer pulling bandwidth using wireless

I moved into a new place and cannot directly connect my computer (no input in my room upstairs). I have a Wireless USB adapter that I have been using. When I am trying to play ANY sort of online game (fps,rts) my latency goes from 50 to over 18k and everyone using the net also expierences lag (while also playing games the game with me). Does anyone else have this problem and/or know how to fix this?