My bias is for nurses to do Hospital Infection Control, because NO one knows better what happens to a patient than a nurse.
That said, you are probably in a good position right now. My suggestion is to get involved w/APIC (
http://www.apic.org//AM/Template.cfm?Section=Home ) and do some networking. If the feedback you receive from those folks is to go to nursing school, look into accelerated MSN courses for people who have prior BS degrees. Seems like you'd do well w/that type of course.
If you do become a nurse, med-surg and/or ICU would be the best placements.
I wish you the best of luck.