Hi OP - not to discourage you, but I've never had any recommendations for a behavioral therapist in this area from this forum, and we've been looking for it for a while for our kiddo with ADHD. What place in Baltimore did they recommend? You may want to call them and ask them for recommendations in this area. I'm curious to know which place because I may call them too!
Behavior therapy, unlike play therapy or drawing therapy, should help you develop specific strategies for managing ADHD behavior. So - target one or two behaviors that you'd like to change, decide what behavior you want to see, set up a system for encouraging the positive behavior and discouraging the negative behavior, in a way that fits your child. Since the normal 1-2-3 Magic or time-out systems don't work very well (or at all) for ADHD kids, or might even backfire, a professional behavior therapist can help you discover what does work for you and your child. I'm not discounting play or art therapy, it just doesn't really help ADHD behavior.
Anyway, please post the place in Baltimore if you don't mind!