I’ve heard of Massad Ayoob. I’ll definitely look into advanced training. One can never have too much of a good thing!
I've taken two of his week-long classes. I recommend him
You might also take a look at fanny-pack holsters for casual times. Also, keep in mind that in a mugging, the first thing the guy's going to grab is your purse, in which case he also has your gun
While I realize it's kinda late to offer this advice, your first criterion for a carry gun is "Is it compact enough that I'd have no problem always having it with me?". A .22 in the hand beats a .44 mag left home because it was too bulky for your evening dress. Ideally, you should have two guns: one that's concealable enough that you will always be able to have it with you, plus another with hefty stopping power for times when you are more concerned about being well protected than max concealment