Hi Nancy,
You have to decide first what are you looking for. MBA is a good degree for business. Are you sure you need something more? PhD is for academia, it's good if you want to be a professor for the most part. DBA is for people who have lots of managerial experience (7-10 years or more), and who want to put it all together. DBA is a PhD in a way, but much more practical. It is a new degree, and most employers know nothing about it.