If you would like to purchase a new domain name you can do so at any time from your Control Panel.
Simply select Domain Registration and then enter your domain name.
Once your domain is registered you’ will need to add the new domain name’ as a parked or addon domain in your control panel. You can access you control panel by visiting www.yourdomain.com/cpanel and selecting 'Parked Domains' from the 'Domains'’ menu.