My wife carries a Springfield XD9 Sub-compact. They are great guns. I got one as well. Have her try one out, you will be pleasantly surprised. Get some night sights for it.
I was recently looking to buy a new pistol and I looked at S&W's M&P 9. It didn't sell me. ( I bought a Sig 226, yes the sky is falling).
The Glocks are great guns once you get used to them. I have several (17, 19, 20, 21, 22, 29 & 34). 9mm is the minimum caliber I would use for self-defense. The great thing about 9mm is that the ammo to practice with is still afordable. .357 ammo is not cheap. You need to shoot, shoot some more, and then some more on top of that. You want her to get used to the pistol. Pracrice makes perfect.
I can't comment on the Sig P245.
Once she is comfortable with the gun both of you should attend a defensive pistol course( If you're adventerous take a tactical pistol course, they'll be calling you guys Mr. & Mrs. Smith). Taking one of these courses is priceless. You will shoot in different situations, under stress, weak hand, how to use cover/concealment, etc. And last but not least, the pistol is nothing but a tool, the brain is the weapon. Program it to run.