Building a site in Magento and transferring to an existing non-magento Domain

[carlboards]

Hi, I'm building a site (e.g. www.buildsite.com) in Magento. When it is ready I want to transfer the site to my existing domain( e.g. www.mysite.com). www.mysite.com is currently and existing ecommerce business that is not on a magento platform. Does anyone know the best way to move my www.buildsite.com to the domain www.mysite.com. Thanks.