I would advise planning what you are going to do with your family. I have no experience or professional advise, but if I were in your position, I would advise having your children wait in their rooms, in a closet or somehow hidden if possible. I would personally have a shotgun with a mounted flashlight in the room and train the wife to use it correctly. I would then use either a pistol with a mounted light or a seperate light to retreive the kids and bring them to the room. All of this should be done relatively quickly, and your wife should be on the phone with 911 while you are doing this. Once everyone is secured in the master bedroom, lock the door and wait for the police to arrive.
That is not necessarily the best thing in the world that you could do, but it is what I would do. But again, I'm just some guy on the internet with an opinion, not a professional.