Hi there,
On initial review of the info you listed, you have a strong profile, congrats! Being a non-traditional candidate can actually benefit you as it helps you stand out from the crowd and be remembered, especially if supported by strong academics and test scores, and yours are stellar. (Congrats on that GMAT!).
Despite the limited extracurriculars, your profile is strong enough in my opinion that IF you create compelling essays (showing who you are, what you'll bring to the class, what skills/experiences you have, why you want the MBA, and why xyz school is right for you), you should be well positioned for any top MBA program.
Just don't underestimate the importance of those essays... that is the one component of the application where you create something from SCRATCH to represent who you are!! Consider getting some feedback from either an admissions consultant or at the very least a friend/colleague with b-school experience. (Side note-- we do offer a free 30-minute consult to further discuss your profile and answer q's, if you are interested you can view that info at
http://www.mbamission.com/consult.php).
As for schools, Haas comes to mind and possibly even Stanford as a slight reach but not impossible. Other strong schools in CA would include as you know, UCLA and USC. For healthcare generally, not in CA but you could look more into Wharton, Ross, Kenan-Flagler, Kellogg, Johns Hopkins... and there's always HBS and Columbia. ;)
Keep us posted on your q's and progress, would love to hear how things go!