The title of the person who writes the recommendation doesn’t matter, don’t get caught up in that.. what matters is what they have to say about you. Best thing you can do is to get your immediate supervisor to write a glowing recommendation. That means the most to the admissions people. I know, I asked that question point blank (after I was accepted).
They wont care about the certs you hold, but they will *love* to see the progression you have made, which sounds pretty good.
Also, make sure in your essays you clearly state why you want to go back to school and get an MBA, what you hope to accomplish with an MBA. More specifically, why Stern is the best choice for you, and vice versa.
I still have my essays if you want to see examples of what got me into one of the top 10 pt mba programs in the nation