-You should have opened the ports in your router homepage (192.168.2.x for most)
-Go to [Start] [Connect to] [Show all connections]
-now.. There should be a side pannel with a few things, Select [Change windows firewall settings]
-Now, Windows firewall is a crappy firewall to configure as you cant select a range of ports to be opened =/
-click on the Tab [Exeptions] at the top of the page
-Now, click on [Add port]
-for the name pur anything you like, would make more sence to put wc3 or something similar but doesnt matter

-Port number: 6112
-Choose TCP
-Now as i said previously, windows firewall is crap ^^ you have to do this 16 seperate times

-Do this as 6112 TCP then 6112 UDP then 6113 TCP 6113 UDP
-keep doing this all the way to 6119 ^^
After this, you should be done!
Worked for me anyway ^^
Good luck