Try changing the listening port in Limewire to 6346

Also incase you haven't already tried. Try turning of your router and wait for 10 minutes before turning it back on.

To find the Gateway IP for the Router. While you are connected to the internet go to Start-->Run. and type cmd then press enter.

On the promt that pops up type ipconfig /all then press enter.

The number that says Gateway IP is the address of the router

Make a note of all the numbers there

IP
SUBNET
GATEWAY
DNS (Two numbers if you are lucky)

note: it's really important that all the dots are in place eg. 192.168.1.101

Also can you try to find the exact make and model of your router. This should help us find a manual online and also it is possible that your ISP uses the default username and password to get into its setup.