Linksys Wireless Router :: Extending Same Network In 2 Different Rooms Using E3000?

I have a Linksys e3000 and a Linksys WRT120NVery simple setup. the 3000 is in my office. There is a cable that goes from this routerto the living room across the house, it is just laying there. Since I cannot get a wireless signal into that room,I would like, using the cable that is hanging there to make use of the other linksys and provide a wireless signal to the living room, all under the same network. In essence, extending the wireless network using the cable in the living room that is connected to the main router in my office.My question is, without touching the master router, how would I set the 2nd router in the living room up?I understand that DHCP on the 2nd router needs to be turned off, and a channel selected so that it does not overlap. Same SSID, Sam WPA2 key.Or would there be a device better suited for this?I do not want to extend the 2 rooms wirelessly I want to use the cable, then use the wireless in the living room for wireless devices etc.