First go to start>run and type in "cmd". Then type "ping yourcomputername" If you don't know your computer name right click on my computer> properties then the computer name tab and it will be next to full computer name. So my pc name is schrags so i would type in "ping schrags" to ge my internal ip address. Your internal ip would be the address next to "repy from" It should be something like 192.168.2.xxx . Now go to
http://192.168.2.1 and log into your router. Judging by your internal ip addy that you had in your first post you probably have an SMC router. So once you log in there should be something like "NAT" tab. Click on that then click on virual server. Under the private ip enter the last 3 digits of your internal ip address which you got earlier. Then under service port enter 2790. then under type choose both (don't know which one it would be). Then make sure the enabled is checked. Then click apply. Now go to
www.whatismyipaddress.com to get your external ip address. Then add a :2790 to it and it SHOULD work. It works for you and your x3 cuz its on your internal network.