plz help me with internet/router prob

[WC3TFT]

I have a really strange problem that no one else could answer so I'm asking it here.
I use a Netgear WGR614 router and the host computer (the one connected to router) is a Windows XP professional with 1GB of RAM, 80GB hard drive. We use the router for sharing the internet and making an LAN. The internet we share wireless but we use a wired LAN. When we play on Warcraft 3 TFT, the LAN games work great, the speed is incredible. But when we play on Bnet, there is considerable lag when I make a game and the people on my router join. It doesn't lag when we play together in someone else's game. It only lags when I or another person on my router make and the people on the router join on BNet.
PLZ HELP I NEED TO KNOW BECAUSE I WANT TO PLAY WITH THE PEOPLE ON MY ROUTER AS WELL AS MY FRIENDS ONLINE!