.38 spec stopping power
First off your distance is too great, as someone else pointed out before me, most self defense situations do not happen at that distance. [usually 21feet and under]
Secondly, forget what they will not sell you around town. Go a little ways out of town and get yourself some winchester 130gr +P sxt [yes that is a hp] or speer gold dot 125gr ghdp [this is +P ammo also] You can even order ammo on line in most states. If your gun does not handle +P ammo then It is marginal for sd/hd. Otherwise a .38 w/4inch barrel or even a snubbie [the four inch is better] Is a pretty good defensive weapon.
I would not let a local ordinance dictate what I carry in my gun, or if I carry a gun, or keep a gun around the house for protection. My safety and the safety of my family come first. You can try me after the shooting is done. I am sure I will do just fine. Most judges and jurys are not as in love with the bad guy as you would think. Take care!
[Remember two in the body and one in the head make the bad guy dead]
Old law enforcement advice.