Wild guess, but the single-stack sub nines, 380s, and .38 specials. Please ignore me if those sorts of things have been slow selling in your location in the past.
I don't even know what to tell you for holsters, but if you could have IWB, OWB, ankle, thigh, shoulder, bellyband, crotch carry, and pocket options over the small and medium weapon size ranges it would probably be a huge help to female patrons. I can't imagine stocking all of the above, but demos for the most common 380, .38 special, and slim nine (may have to wait a few months to figure this one out) would probably go a long way. I'm a guy, I have an OWB and IWB holster for my 45 and a crotch carry option for my .357 snubbie. My wife has me convinced that those three options pretty much suck for women. I caught something about OWB and paddle holsters are okay on odd numbered Tuesdays but none of that works with a dress...
I'd bet you couldn't go wrong with pallets of .45 ACP and 380 ammo either.