One thing that certainly will help is if you forward a port on your modem/router. Are you willing to do it? I'll give you the instructions:
1. You will need to set up a Static ip for this to work!. Instructions are in a brown link on the 1st line of the following link.
2. Netgear WGR614 for port forwarding via Web Interface & use Port 6346.

3. Within LW Force IP: Force IP instructions & sample image

4. Rather than go unprotected without any firewall. It would be best to configure it to allow LW full access: http://www.limewire.com/english/content/firewalls.shtml

See how you go. Oh by the way your modem has an internal NAT firewall. That's why I'd recommend forwarding a port. If you were playing net games or video conferencing you'd need to open many ports. But for LW it's only one!