it might be 3389 and 3390...try both of those and see what happens...
allow both ports in your firewall and forward them to the correct ip address
i believe those are the correct ports but not 100% sure...
if not u can also try 5800 and 5900
Remote desktop uses only 3389 AFAIK. 5800 and 5900 are used by VNC.
If you have several PCs you wish to be able to connect to remotly, you could map a different port to each PC, like I am doing:
3389 -> server's port 3389
3390 -> PC1's port 3389
3391 -> PC2's port 3389
And type the port number in the box in the client (eg yourip:3390 to connect to PC1)