To add, when using ports (like 8129) be sure to put http:// in front of it. Internet Explorer doesn't always browse to ports properly with no http:// in the URL.
Try:
ipconfig /all
This should show you your external IP address. I use Deerfield's free DNS2go product to give myself my own domain name, so that I don't need to know the IP. You can get it at
http://www.d2g.com. If you do that then you can then get to your server using
http://brunolucia.d2g.com:8129 (or whatever name you chose).
-Dan