Ubuntu Networking :: Access SSH Machine Through Router?

I have two laptops with me here at school, one bigger one [home computer], and one smaller one [netbook]. I take the smaller one with me to class and when I'm out and about, however, I keep all of my things on the bigger one. I would really like to be able to set up some sort of SSH port forwarding for the bigger machine so that, when I'm out and I realize I left file X on my home machine, or I want to listen to a certain song, or whatever, I can just scp it to the netbook. The issue is, at my dorm, I'm stuck behind a firewall and can't just set up a SSH daemon and port forward through the router, I need a more clever solution. I do have a home server (not with me at school), which I commonly use for transferring files. Basically, I'm wondering if there is some way I can SSH into my server box, with reverse port forwarding so that, when I am out and about, I can just log into my server and copy files from my home computer for use on my netbook. I've tried a couple of solutions which come up from google "reverse ssh" but haven't been able to get them to work. A step by step guide to doing this would be great. Again, the setup is:

Home server [ssh-able]
Home Computer [behind firewall, can't ssh into at the moment]
Netbook []

Want to be able to SSH from Netbook to Home computer, probably using Home server.