Once you have your new WordPress site setup with your content the way you want it from the dev site:
=> The nameservers have to be changed for your domain on the dev server to the new WordPress hosting nameservers. (I usually wait to cancel old hosting for about a week to ensure propagation time for the domain's new location.)
=> You also have to change the domain name in WordPress (Settings > General). More on changing WordPress URLs here.
=> For email the MX servers would also have to be modified to reflect your new email service for the domain. GoDaddy does offers a migration service to Office365 if you want to use that and need assistance.
=> Next you will have to change all the URLs within your content from the dashed domain that you installed WordPress on to the non-dashed dev domain that you want to use. There's a plugin for that!
Judith "Worry is a misuse of imagination." ~Unknown