if you want to do it on the cheap...
buy this:
TL-WR841N
flash this onto it:
DD-WRT
follow this guide:
Repeater Bridge Guide
I believe you may not even need to put DD-WRT onto it as it says it supports a wireless bridge mode out of the box, but the reviews on amazon for the router look good
here, it is cheap as fuck, and should do nicely.