This should get you started
PA IDPA clubs
USPSA/IPSC clubs in PA
there are of course others but these are two of the more popular.
IDPA is a little easier to get into, you should be good to go with what you have. A good holster, mag pouch (though you can use your pockets if you don't have one) about 100 rounds per match, a couple of mags, ears, eyes and the gun and you should be ready.
IPSC you will need a little more ammo and a few more mags.
Find a club and go out there, most places are really friendly I find and will do whatever it takes to make sure the new shooters have a safe and fun time.
I will warn you it is just as addictive as buying guns.
good luck.
P.S. don't get intimidated by the shooters, they have been doing this a while and are really good. You will get better and better, remember it is about fun and improving your gun skills and you will enjoy it more I think.