Not sure about the router or the game, since I don't have either.
But this is what I do, when ever I update firmware or get a new router.
There is something called QoS (Quality of Service), it is best if you use a mac address.
Put in both mac addresses into the QoS area, and set one at the highest, and the next one step lower.
See if that helps any?
Have you tried it with connecting only your two computers, how many computers do you have hooked up to the network, do you have any switches, maybe faulty wiring of cables or panel connections (the things in your wall).
See if it works if you direct connect your PC to the router to the modem. Open the correct ports if that doesn't work while still connected.
If all else failes, try disabling some things from your firewall on your router.
I was having some issues with the F@H and Winamp Auto-Tag that was because of security/firewall settings.