It depends greatly on your desires, likes, dislikes and future goals.
For example, have you ever considered getting a masters degree? If you wanted to get a masters degree anyway than that might be a good path for you. The next question would be whether you see yourself going towards the technical side or business side.
If you want to focus on technical solutions to business problems then you might consider a masters degree in information systems.
On the other hand, if you want to be working closer to the business side and focus on the operational and process aspects of the business the you might consider an MBA.
Regardless of the path, I strongly recommend that, in addition to one of those degrees (or even without one), you should take some of the business analysis specific courses offered by many of the training providers that specialize in business analysis training. These courses cover specific topics such as: requirements elicitation/analysis, requirements management/communication, requirements and solution modeling, etc.
- Adrian