A 22 caliber handgun is not a defense weapon. In a bad situation you will be unlikely to hit where you are aiming to begin with, and you will be hitting it with a bullet to small to do enough damage to stop the threat. If something is trying to kill you, and that is the only time you have a right to use a weapon, you don't want to rely on a bullet as small as a 22. You are almost better off without a gun than with a 22.
Anyone that would tell you that a mag of 10 rounds of 22 cal will stop anything you will face does not understand the reality of self defense with a handgun.
You need a minimum of 9mm for defense. No police force in the country allows officers to carry anything smaller. The above poster was right, look at the Kel-Tec in 9mm. Buy a 22 for plinking and practice, but don't rely on it for defence.
Here is a good website to visit to learn more about handgun for defensive purposes:
www.glocktalk.com
jim