nods, your best bet is this
in windows firewall make an exception for the .exe of the server, and also for the port you wish to use
in your router's settings, forward the port you're using to your internal IP
and as an added bonus, just so if your external IP switches a lot, its much easier to lead your team using a free service from DYNDNS.org .. just setup a free account, and make a hostname using their free subdomains (I always use game-host.org) and either go to their website every morning and refresh your IP (or however long it lasts before renewing) .. or you could make some kinda fancy startup script to do it for ya