probably not what you want to hear, but here is what you can do:
Setup the router and modem in one part of the house, and run a wire to your accespoint, wherever you want it. Not exactly a repeater, as you have to select the strongest signal to work with, but its easy. P.S. You might have to adjust the channel and ssid on the routers, or you might be able to keep them the same, depending on the quality of your router.
hope that helped