Hi Erin,
My vote is AC cloud and upgrade MediSoft.
Overwhelmed! is the reason why. Don't take on more stress.
If you have a great IT company who can give you a turnkey client/server set up, then that might be the right answer. Money is not the problem, too much change is the problem.
Definitely do not put your office through a PM change on top of all the stress you have, or you will be working 100+ hour weeks, and possibly get dwindling revenues until you have mastered it all.
You will survive!