Can't connect to battle.net and I think it has to do with router firewall

Hello, first of all this is my first post so I am sorry if it is in the wrong place, I saw a similar thread here so figured this would be the right place.

Anyways, when I open Starcraft II I will be connected to the internet for about 10-15 seconds, then suddenly my internet no longer receives a connection. During this time I can try to quickly log on but there is basically no point because it will soon boot me off battle.net and tell me I can play in offline mode. I am on a 2Wire router and get internet from another computer. I also turn off my firewall and antivirus before opening the game. At first I thought the problem must be something to do with the computer that is hosting me blocking Starcraft II. I told the problem to my stepdad, who I get internet from, and he went to his router firewall (which I have no idea how to get to) and unblocked Starcraft II/battle.net. The problem seemed fixed, I went back to my pc to play and battle.net worked perfectly. When I woke up the next day the problem was there again. All I can think of is that my router firewall is blocking it or something, but I have no clue how to even get to the port area or the firewall of my router to forward a port or turn off firewall. Does anyone know what I could do to fix this?
I have had this problem a while now and would really appreciate any help, thanks.

 

Might try setting up port forwarding/triggering on the router to your computer's IP.

See here for ports:

http://us.blizzard.com/support/article.xml?locale=en_US&articleId=21109

 

Thank you, I thought I might have to do something like that..
I know it sounds dumb but I dont know how to get to the place where i can foward ports and such.. I am running a windows 7 which I have only had about a month