I was in a similar situation as you early in my firearm hobby. I wanted something for those Really Bad Days (RBD). The only firearm I had was an old .22 rimfire bolt action rifle.
As it turns out, this was a great way to start, pinching every penny making every single shot count the few times I could go to the range. At one point I could nail any target up to saucer-sized out to 100 yards easily with that rifle.
OK, on to your situation:
If you get really good with what you have now (a 9mm Ruger handgun), and more importantly train that brain between your ears, then your mental attitude and familiarity with your existing equipment is much more useful than getting the latest featured handgun on the cover of American Handgunner.
Here's a useful fact that most people want to ignore: ALL handguns are questionable fight stoppers. Some bad guys are obliging and go down with one hit, or even without you ever firing a shot. However, anyone with a good amount of "fight" in him (or it) will keep going for an alarming period of time. This hasn't changed whether the gunfight was in the year 2000, or Tombstone Arizona in 1881. If you read the details of that fight carefully, nobody went down with one single handgun hit, though the involved shooters were deadly earnest in their efforts and had probably the best of the period in .45 LC caliber.
OK, more practical advice:
Practice dry firing to a PERFECT sight picture and trigger squeeze. (check that it's unloaded first!!) Then practice holding the trigger back while you rack the slide with the other hand, and then do the follow-up trigger press only releasing the trigger as far as necessary for the sear to reset. You should hear/feel a "click" when the sear engages. At this point start pulling the trigger again. Notice the first and 2nd trigger pulls are vastly different.
Do this 100 perfect times a day.
Now do about 50 of the above using both hands, and do 50 perfect clicks the same way only holding the handgun with your right hand. Repeat with the left hand.
Then add coming out of the holster FAST and on target.
Then add strange positions: aiming around corners, hiding behind furniture, sitting on the toilet, etc.
Add the mental picture of what you're doing: Where you're aiming on the opponent, and what you'll do if he keeps coming.
If you dry fire so much that you know the feel of the handgun better than the steering wheel of your car, then when you can afford to shoot live ammo, the training time will be much more effective.
So what if you don't have the biggest baddest gun in the West? If you're really good with it, you'll be 100 times more capable than someone who only picks up his handgun once a year. It's what's between your ears that saves your @$$
Hope that helps.
Edmund
