It looks like it's up and running OK (super late reply though).
You can always keep your domain, since you're using a registered domain name, but I don't see a lot of support or tools for importing/moving blog.com blogs. My advice would be to keep regular backups and since blog.com looks like it's working for you, maybe slowly move (manually if there is no other way) to another platform. Then when you've got everything moved to Wordpress, Blogger or whatever platform you choose, update your domain name to point to the new blog.
Moving platforms is never easy. Even if there is an import tool, it's still work.