Your router is fine. It's the kludge of putting a switch or hub between the DSL modem and the router. I don't know how you made it work but unless your ISP's DLSAM delivers more than one ATM tunnel to your DSL modem, you're gonna get one MAC address and one IP address from your ISP.
You can easily prove if I'm wrong. Fire up all your computers and see what IP address they have: Start -> Run -> cmd ipconfig Also extract the WAN side IP address from your USR8054. If they're all the same, you have a mess. If they're all different, I wanna know the name of your ISP so I can subscribe. I could use a mess of free IP addresses when I'm only paying for one.
Since you're in a rush and have to get back to work, I'll just tell you what needs to be done. Get rid of the hub or switch between the DSL modem and the router. Plug all your wired PC's into the LAN side switch on the USR8054. If you run out of ports, put the hub or switch on one of the LAN ports and use it to expand the LAN side of the USR8054. Leave the computers set to get their IP addresses via DHCP. You may need to reboot or to run: ipconfig /release ipconfig /renew to get a new IP address.