My wife was against guns, but I'm against high heel shoes. So, she keeps her high heel shoes and I keep my guns. Been happily married for 31 years.
You're the man of the house. Your job 1 is to protect your family and I congratulate you for taking the responsability seriously. Explain that to her and she will come around.
After your first one the second one is much easier.
Back to the gun, I'm all for a G19 because it is so versatile. But you need to hold a Beretta 92FS. You can't get one for $500, but you're in luck, you can get a Taurus PT-92FS which is a licensed copy for $400.
See what Wikipedia says about the Taurus http://en.wikipedia.org/wiki/Taurus_PT92