|What kind of connection to the internet do you have? Cable, DSL, T1? The Linksys router you are trying to use won't work because its a NAT router, and like you said, will only work with 1 IP address. I was never successful with setting up static routes on Linksys routers.|
Typically T1 providers will provide customers with blocks of IP addresses. Depending on the WAN technology used on the T1 link (Point to Point, Frame Relay), the customer's router will need a T1 WIC card which gets assigned a single IP address and subnet mask. The customer is then provided with a block of IPs to use on their internal LAN. One of these IP addresses is usually assigned to a Fast Ethernet interface on the router, and this becomes the default gateway for the nodes on the LAN.
Routers else where on the internet will be setup and have their routing tables configured to route packets destined for your block of IP addresses to your LAN, hop by hop. When working with Cisco routers in basic networking environments, assigning the IP addresses to the appropriate interfaces is usually enough and requires no technical manipulation of the routing table for your network to operate properly.
If you can provide more details about your connection I can try to point you in the right direction.