QOS with the router http://techpaul.wordpress.com/2011/05/17/restricting-roommates-internet-use-continued/ (2 articals there)
If you can put a program on the other peoples computers, a simple net limiter on each computer would work.
Setup a second wireless connect with a cheap USB wi-fi thing, and a cool program called Virtual Router.
Being at the far end of the signal , you might not even be negotiating the max speed of the connection to begin with, so if everyone gets the same time slice, you get less data still.
Balance out the distances and therefore strength of the signal, by putting the router more centrally located, or change the antenna type to a more directional style .
There is a cheap trick to use when wireLESS isnt strong enough, run a wire that the radio waves go down , it does not have to touch both antennas to get the signal closer to the other antenna. A bit crude but interesting. the wire can be very small diameter.
Improve the max speed of the wi-fi to begin with , by using N router, and N capable client connections.
Achieve better cooperation with other users, and thier use of the connection. Help THEM by showing them how to limit use by blocking adds, dumping flash junk, killing scripts, or even shutting off pictures. Multiple connections like sharing stuff would kill your bandwith, try and centralise these downloads on a wired system.
Very expencive bandwidth limiting software that is used by hotels and restraunts and all. I did not yet find a cheap easy program that works like that for windows.