From within your network try going to 192.168.XX.1 (where XX matches whatever IP address you've been given) in a web browser. With any luck you'll be given an administrative interface that lets you set up port forwarding, etc.
If I understand your setup correctly then what neo suggested won't help you because the problem isn't you getting out, it's you getting in from the outside.
So, if you can't get the administrative interface and change your settings, then what you want is the opposite: a reverse tunnel. That setup requires that you have access to some machine somewhere else which isn't behind a firewall which doesn't allow incoming traffic. You could try
http://techrepublic.com.com/5100-108...ml?tag=nl.e011 and
http://www.macosxhints.com/article.p...50222062346277 for a bit of information (for Linux and Mac OS X respectively). There's probably a way to do it on Windows, too (Google for reverse tunnel).