First off, Congrats on the Mustang. You mention wanting to go faster, but establishing your long-term goals will give you a path to follow.
Mustangs are a lot like College courses. If you don't have a good plan up front, you'll spend years agonizing where you're headed and end up spending twice as much as you should.
This website is THE RIGHT PLACE to learn about going faster. Unfortunately, these people donate blood and sleep in tents to make their cars faster! This is a pretty extreme performance group, and thus the previous warnings.
I myself have a mildly tuned car right now and I am happy for now.
First, find out what local shops support modifications. The guy in Woodland Park ought to know, so you can PM him. You want to find a shop with a Dyno. You then go to that shop and get an idea of upgrades and cost.
Because you are in the Springs, you are at a disadvantage for air. I would recommend forced induction, but you have to be ready to drop $3K to even open that door.
A cold air intake and tune will do wonders. I have family there I visit annually and my car ran good on '91 octane while there. I have a C&L Racer intake with DiabloSport tuner.
As stated, find out what the locals are using and what shops support late model Mustangs. Nothing worse than paying for things and finding out you're on your own. You don't want to do anything that can't be supported or undone.