An MBA program with a strong healthcare focus

Honestly, from a quick and rough glimpse at what you've wrote, you're definitely good enough for top 15 b-schools; however, lots will also come down to your work experience at the bank you mentioned, your letters of recommendation, your essays, as well as your extracurricular activities. View the application as a holistic process - not only does academics matter, you need to be able to communicate effectively and convince people of your core capabilities as well.

Tips to make you more competitive (and by no means is this be-all-end-all): start taking on some leadership roles both inside and outside of your professional career; initiate ideas and drive your points home; take these few years to explore what you really want to do (Why get MPH with an MBA? I'm not doubting your idea, but just be sure to know that for yourself the reasons you're wanting this dual degree); do well at work and build rapport with peers and supervisors. Other than that, pick up some extracurricular activities that interest you (if you have time). If you enjoy running, run some marathons and start a club; if you enjoy volunteering at shelters, do that - basically, find something that will say more than you're analytical and good at numbers (which schools will automatically know you're good at given your work experience).