Your ISP assigns an IP address to you. This is generally the only IP address you get. If you just have one computer hooked up without a router and issue the "ipconfig" command, you will see this IP address. When you set up your router, it should automatically pick up this IP address when your modem is connected to it. Your router should now have an address similar to 192.168.0.1 (some routers may use a variant of that). If you open your web browser and enter http://192.168.0.1 you should be directed to your router. If you click on "router status" (or something similar), you should see your assigned IP from you ISP. It is not unusual for it to start with two numbers, but i also may start with three. You should then click on "attached devices (or something similar). It should show both your desktop and laptop with Ip address similar to 192.168.0.2 and 192.168.0.3. Within your home network, you could address these computers using those addresses. Again, on your router see if there is a "port forwarding" option. Click on it and make sure you have a "remote desktop service". You can either enter the specific RD port or (for testing purposes) open it up using a starting port of 1 and an ending port of 65534. There should also be an IP address to forward to and it should be the address of the computer you want to remotely connect to (I assume your desktop). This should be a 192.x.x.x number. I apologize if some of this is already evident to you, but I am not sure as to the extent of your expertise in this stuff.
One other thing... If you still can't get it to work, contact your ISP and see if they allow you to use the RD port. For instance, Charter does not allow users to use the web or ftp server ports.
LiL pun... what's your ISP? I'd like to scan your uhhhh... network... to see what I can find... Really, what's your ISP? Is it your school's network? They might not let you. Use that dyndns.org service to connect via a hostname instead of mucking around with IP addresses... that service finds out what your PC IP address is if it changes.
hey Pun, Im tryin to finish some work before I go to league, but Ill be in the chat room after the game (its a late game so I should be in there before the end) come in there and we can do some real-time troubleshooting if you are free. FYI, the chat link on the main CF page will (normally) get you there no problem