You can open port 80 even if you were given the router. I will give you a small tutorial below.
If you want a even more detailed tutorial go to http://portforward.com
Step 1: Press "Start" button. Then in search bar type cmd . Open CMD.exe as Administrator.
Step 2: Type "ipconfig" without the " ".
Step 3: Then find the default gateway.
Step 4: Open your browser and in the URL bar type the default gateway IP exactly without anything else.
Step 5: a box should pop up asking for login information. Default should be username "admin" password "admin" or username "admin" and password box blank. (if neither works ask the person who set it up.)
Step 6: If you have a Linksys router then go to applications and gaming. Then type port 80 in the start and port 80 in the end.
Step 7: Then where it says protocol select BOTH.
Step 8: In CMD, find where it says IPv4.
Step 9: in the box on your routers we page type the last 3 numbers of the IPv4 address.
Step 10: Finally, enable it and save all settings.
If needed any more help please private message me. I can help on Skype video call for live help.