You will want to add the "live" url to the list of Portal Aliases.
Then you will need to:
1. Move your database AND web directory to the new site.
2. Edit the web.config file to connect to the live database server.
3. Set up IIS on the live server to use the correct URL.
You should set this up as a separate website. You don't (normally) want to make this a subdirectory in an existing website.
You might find these two tutorials to be helpful. I find the Evotiva DNNBackup module to be an invaluable tool for moving sites from server to server.
http://www.dnncreative.com/Tutorial...fault.aspx http://www.dnncreative.com/Tutorial...fault.aspx