Well the steps I gave should have gave you the Apple Wireless Password :o I'll post picture references for you incase there was a miscommunication.

System Preferences>Network>Select Airport>Advanced
This should access you to the information about all of the networks you have ever been connected to.

Select the Airport
you are currently using>Hit the Pencil or Edit Button>Click Allow
You have to make sure you pick the airport you are using now and not the first one that pops up because it contains the password that is connected to your ip.

Once you've hit allow, click the box that says show password and your password will appear.
If you have done all of this and it is still giving you the wrong password or no password at all, then I am out of ideas. I hope that you find a way to successfully port forward :]
OH I ALMOST FORGOT:You can do standard PC port forwarding procedures on a Mac through FireFox, that is how I port-forwarded.
http://www.portforward.com/Use that link, it worked for me. Once again, best of luck!