Transform your old WiFi router into a WLAN Bridge using DD-WRT:
You may be able to upgrade your old router with a different firmware that will allow it to act as a wireless bridge. That is, turn your old router into wireless bridge. A wireless bridge allows you to connect one network to another over the airwaves, rather than having to run wire from one room to another.
–jeroen
via: How To Turn An Old Router Into A Wireless Bridge.
The Wiert Corner - irregular stream of stuff 