If you are into a lil bit of DIY, pick up a linksys WRT54G/GS (v.1-4) which should sell like dirt cheap. Install Tomato firmware on it, and you can use the router as an extender/repeater, bridge and what not. Alternatively, if you have an old wifi router lying around, check its compatibilty on http://www.polarcloud.com/tomato and follow its steps.