As I can see adverts on your site it sounds as if you have just paid the $12.95 registration fee for a domain.
You can use that domain with a site hosted elsewhere but if you want to use it with a Bravehost or Bravesites website you have to buy the full Pro hosting package ($99)
It is a common practice among webmasters to mix and match services from different providers - in fact some consider it good practice to have domain registration and hosting handled by different companies. Also webmasters often use free hosting services to try out features before committing to a contract. So Bravenet will see nothing odd in your having a registered domain and free hosting.