Hardware :: Hooking A G5 To A Wireless Network Using An Ethernet Cable

I have two G5s, one next to my ethernet/DSL line which plugs in directly for internet, and a second out in the living room where there is no DSL line. However, the house has wireless via an Extreme and two Xpress socket-plug-ins. My mac guy told me that I should be able to hook the G5 in the living room directly into the Xpress next to it via an ethernet cable (the living room G5 does not have a wireless card in it) and the wireless internet should link up via the Xpress to ethernet cable to living room G5. ? He said to make sure I had the ethernet configure box set to "using DHCP" which it is and it should automatically find the right IP address. When I try it, I get nothing though, just a message that there doesn't seem to be a network connection.