There are a couple other posts about moving a site from a testing server to a live server but here is a real quick outline.

Backing up.  All, EVERYTHING for your site is in the database.  If you loose the datbase you loose the site, so backup that database.  You will need to backup your web.config, siteurl.config, any apsx files you changed by hand and all the files you uploaded to your testing server.  For example if you have the gallery module installed from here and you have uploaded photos you should backup everything in ./portals/0/gallery/. 

FTP all of the files from where ever you installed them on the test server to where you are putting them on the live site.  Add the new portal alias to the site for your new domain name.  There are several ways to do the database but the easyest and safest is to do a backup on your system and a restore on the new system. 

Confirm all of your files made it across in the ftp and your host has given proper permissions to the sites directories. If there were no errors in your DB restore use IE to surf to your new domain that you added to portal alias. If you get redirected from there back to localhost use your favorite tool to get into the portalalias table on the new server and remove the entry for localhost.

You should now be live.