Sounds like your router might be the issue. Either that or your ISP. (Keep in mind most wireless devices use NAT or similar which acts as a type of firewall. The question is whether it has UPnP support & if yes, is it running efficiently.)
If you can list your full set up including how it's networked will help us greatly in trying to help you find a solution. System details - help us to help you (click on blue link)
Do you have more than one LW running on your network, if yes, is it using the same connection port?