If you have a static IP Address then you write on page address of your firefox(Internet explorer) http://www.whatismyip.com. Then you copy/paste your IP on your page address so and press enter. Then you will be in your personal router's site. You open the ports from there. The address is:
http://YourIP/ and then use the search button here to find a post that Procrustis sent cause I will not explain you what to do to open the ports from this site.