If you want to transfer your MyWebSite.tv site to (.com) the best way is to swap the database entirely.
You need to export one database and import it in the other place. But before importing it you should replace all strings with the old site, using this tool:
1. You export the database from MyWebSite.tv (using phpmyadmin)
2. You go to the app I've linked there, choose to replace MyWebSite.tv with MyWebSite.com and do the replace.
3. You take the outputted database and import it in your MyWebSite.com
4. You should now be able to log into the new site with the login from the old site.