I have a gun, but I also know how to use it and pretty well at that. I am not sure I would recommend to anyone getting a gun for protection unless you are trained. Chances are high that you'd hurt yourself or have it taken away from you instead.
The best defense is a good offense. Get really serious about documentation. Get a nanny-cam, and possibly a security cam for your front door that can hook into your computer. Tape and video everything. Empower your oldest to be able to know right from wrong. Have a bag around for a quick exit. Have a safe place to go to at any time of the day or night. Take a self defense/hand to hand combat class.
This is serious business now. Plan for anything and be prepared.