Transferring Domain

I’m currently hosting a WordPress of the site, using my friend’s hosting, so the domain is currently…

http://example.example.com

And I just bought a
http://example.com
From 1&1 hosting. On their site, I changed the DNS settings to..

Primary: ns1.wordpress.com
Secondary: ns2.wordpress.com
Third: ns3.wordpress.com

I’ve tried editing wp-config.php with this line

define('WP_SITEURL', 'http://old.example.net/');
define('WP_HOME', 'http://new.net/');

Which is results in the new one opening as “Link Broken” or something. The other 2 variants,

define('WP_SITEURL', 'http://new.net/');
define('WP_HOME', 'http://old.example.net/');

AND

define('WP_SITEURL', 'http://new.net/');
define('WP_HOME', 'http://new.net/');

And they all result in the same thing. I’m not sure if I’m putting it in the right place, I’m putting it here –

<?php
/**
Loads of comments
*/
Script I put in
// ** MySQL settings - You can get this info from your web host ** //
/** The name of the database for WordPress */
define('DB_NAME', '______________');

What am I supposed to do? Is there more I should edit with the DNS on 1&1, or what do I need to change on WordPress? Also, keep in mind I want to keep my hosting where it is, just change the domain.