linksys file sharing xbox nightmare

ok so I have a network at my house and there are about 30 people on a big hub the problem is that I only have one cat-5 wire running into my room so I bought a linksys WRT54G wireless Router to let my wireless laptop get wireless and so that I could hook my xbox and desktop computer up to it.

Now that I have it all installed I cant get filesharing on my desktop or laptop I cant see any other computers on my network that are hooked up to the 30 port hub. I also am unable to see any other xbox games on the network

Please help me Im lost Ive tried to tinker with the settings in the routers configureation menu 192.168.1.1 but to no avail. Im sure taht these problems are directly related but I still have no idea what to do. if you could help out I woudl really be gratefull