I'll be back in Columbus Sunday, but theres an easy and free way to do this.
Like dragknee suggested, it's alot easier if you can assign a dynamic name to your IP, and use a third party updater to keep it current.
http://www.dyndns.com/
Once you get that taken care of all you really need to do is setup the router. Since most SOHO routers use NAT, you have one public IP and usually a class C 192.x.x.x local network. Trick is to use port forwarding and a static IP of the desktop you want to access.
So set your dekstop up with a static IP, set the DNS to point to the gateway, usually 192.168.1.1, or 192.168.0.1
You may have to dig around a bit, but most routers have port forwarding by rage or some sort of UPnP page. You want to forward port 3389 and 3390 ( for sound) to your desktop's static IP. I beleive it's TCP for 3389 and UDP for 3390, but it may be both.
When you're on the road, punch in your dynamic dns, say anthony.rules.com:3389 (may need to specify port, may not) into the remote desktop client and shaaazam, you are connected.
Note: It's a good idea to have strong passwords, and if you beleive in security through obscurity, change the Terminal Services listening port @ Regkey: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\TerminalServer\WinStations\RDP-Tcp\PortNumber