If was you I would get rid of the desktop modem and get the networked one (unless that's what you're referring to). You know, the one with an RJ45 jack at the back.
Then get a broadband router. I had a Netgear
WGR614 with the iBurst box. Worked like a charm. I gave it to a friend when I left S.A., and three years on, she's still using it. The WGR614 gives you wired and wireless, so you can hook up your PC via cable and ipod via wifi. It gives you the added advantage of a firewall in front of all your devices.