@EchoesAndReflections
You can use the same custom domain for WordPress blog.
Steps to follow (if you want to go with self hosted WordPress):
1. First purchased a hosting for WordPress from any hosting company.
2. Install WordPress on temporary URL provided in hosting account.
3. Import all the posts and comments from blogger.com blog by using default imported tool present in WordPress dashboard.
4. Follow remaining steps mentioned in this article.
5. Change the DNS in Godaddy account for hosting account.
6. Final step, change WordPress URL from temporary to custom domain.
Hope above steps helpful to you.
Thanks,
--Nitun