Did you check out UPnP?? If you found that your modem doesn't have it, you can try port forward. To enable UPnP in the modem, either see the manual or ask your ISP to help.

Just make sure your ISP is not blocking p2p. Some do & you should check to see that this is not a prob before you go any further.
Here's how to port forward...

Step 1: Set up a static IP address. This HAS to be done first:
http://portforward.com/networking/staticip.htm

Step 2: Port forward through your modem:
http://www.portforward.com/english/r...d/Limewire.htm

Step 3: When port forwarding's in place, within LW, tools > options > advanced > firewall config. Tick manual port forward & enter the port number you've forwarded (6346 is the default). Apply. Your listening port (on same page) will be the same number.

You might have to restart LW to effect the change, I can't remember