you seem to have strong background, and i assume gmat would not become a big issue for you.
to succeed, i think you should choose carefully where you apply. do lots of research about schools and faculty. the most important part in my view is to find a good fit between you and the school you apply for. more specifically - between your research interests and the departmental "research agenda", and some faculty memebrs' interests.
this fit should be made clear in your SOP, and can be boosted by making prior contact with potential advisors.
i think applying to NYU would be either unaffected by your previous studies or work in your favor if some professors have good memories of teaching you (you can politely email them and ask...)
and stick to this forum of course
there are lots of helpful tips in these forums (also the MBA forum....although not all relevant for phd aspirants like us).