Networking & wireless forum: Second router on 2Wire network

I am trying to set up a wireless connection for a friend, and I am running into a little trouble. The issue is that they have a DSL connection, with a 2Wire router/modem. However, the router does not have the power to reach the laptop from the other end of the house (for some reason, they seem to have some interference from the back end of the house.)
I set up a second router, with Tomato firmware, that had a higher power setting, and it reaches the laptop on the other end fine. However, I cannot connect to the network. I believe this is because of an issue with the 2Wire router.
How can I set up the new router as a second router to have wireless clients connect to the new router through the 2Wire router? I tried selecting Client and Bridge, and both caused the wireless network to disappear from the list of available networks.
I am not sure what I am missing here.
The second router is a trusty old Linksys WRT54GL. There is one desktop computer, and one wireless laptop that we are trying to connect from a room at the far end of the house.

Any assistance would be greatly appreciated. Please let me know if you have any other questions.