Sorry to hear about crime rising in your neighborhood. In reality, any time your are up against a team of thugs, you are at a serious disadvantage. You do not know if the guy on the corner is a by stander or a look out. I would resort to deadly force only if you really felt threatened at that moment. I know that compliance does not guarantee safety, but 2 or 3 on one isn't great odds either.
For your house, I would strongly recommend that you get a good alarm system and a big dog. While I know a scumbag would shoot a dog without giving it a second thought, the dog will still be a deterrent and reduce the chance of a surprise attack. Make sure your house is lit up and that you plant inhospitable plants such with thorns. Make sure there are no hiding spots where you may be easily ambushed. These preventative measures will make your house seem a lot less inviting and prevention is always better than a cure. Make sure you have good sturdy locks on your doors.
Make an emergency plan and try to create a safe room. This safe room should give the best tactical advantage and be the meeting place if the alarm goes off at night. As already suggested, a long gun such as an AR or AK would give you much better firepower and would tip the odds in your favor. A simple pump shotgun with buck shot followed by slugs is also a good option.
If you're out and about, keep your head on a swivel. Situational awareness is key to preventing problems, or stacking the odds in your favor at the very least. I like the idea of the Glock 26 since Glock 17 mags work for it.
Good luck and stay safe!