Welcome to the board.
There are so many handguns on the market that would fit the bill. Best thing to do is handle all you can at the gun store, see what works for you ergonomically.
Generally speaking 9mm will be comsiderably less expensive to shoot than 45. Unfortunately the 'gun scare' of 2013 has depleted most stocks of ammo so that point is moot for a few months.
Personally I'm biased toward CZ but that doesn't mean it will work for you. Only you can make that determination.