Hey,
Alright, you got the RCON Port and the Client Port. You might have one other port to worrry about too, the server list port or query port. Im not sure if vcmp has that, if anyone could back me up that would be great. But, you can find your RCON / Client Port in your config.ini. Just forward thoes, both UDP and TCP just to be safe, and you are on your way!
I think portforward.com is a good site, never really checked it out though.
Cya,
Tommis