I'm sorry to hear about your robbery. It is my understanding that Cali is fairly particular about which firearms you are allowed to own/keep in Cali. I'm sure one of the Cali members will be by with a link to the list of DOJ-approved firearms available for your purchase, online or at a local Cali gun store.
I do wonder though, were you robbed in your home, or will you be looking for a firearm that you can carry on your person? This would require you to get a permit to carry a concealed firearm, which could take a lil time & some training.
If you are talking about a firearm for home defense & to be kept at your home, i really find my Mossberg 500 pump shotgun very comforting in that role. This firearm can also be used for shooting trap or for hunting, should you have interest in that. I do not live in Cali, though, and am not 100% sure that you could purchase a Mossy500 or more likely whether or not you could equip it with a shorter barrel for home defense (18.5" is limit i think). In MS, where i live, shotguns are simple to purchase at your local sporting goods store, as is ammunition for them.
Good luck to you.