Nat hole punching proxy server application required

I have a proxy server application written in visual basic. When you install it, it creates a proxy server on the machine its installed on. It auto configures its own username and password and port. It then reports the credentials to a database which is displayed in a webpage online. But, it only reports the ip of the nat, the internal ip. I need a similar app created to be able to punch a hole and report and use the outer ip address of the connection that its going through. This is called nat hole punching. A stun server perhaps is what i need. I want the fastest possible method of transferring the data. When I install the proxy server onto a machine, I need to be able to read the credentials from the database it reports to, and use the proxy server from any machine, not just behind the nat. if you think you can do this.. dont apply. If you dont know what hole punching is, dont apply. I have had enough people making claims and then trying to pass off an ordinary internal proxy.