Xbox 360 and linksys

I am wondering if there is a way to hook my linksys router up to another router that will pick up the signal so that an xbox360 can plug an ethernet cord directly into the back of it. We tried two different wireless cards for the xbox, and they do not work, but the port works fine. So, is there a way to link two routers without running wires so that the xbox can run off that signal?