Hello GWarren,
If you already have the supply current coming into the present box, then you will first, make sure the power is turned "OFF" at the breaker panel before doing any work on this circuit.
Once the power is off, you would then run the supply, (incoming power line) to the bottom screws of the receptacle (outlet). the Black (Hot or Common) wire goes to the brass colored screw, while the White (Neutral) wire, goes onto the silver colored screw. Hook up the bare copper (Ground) wire to the Green grounding screw on the outle.
Now, you have power going to the outlet. For the light switch, it (I'm assuming) will control a light, either on the ceiling or wall mounted ones, etc. In order to do that, you would run another wire, typically #14/2 Awg with a ground, from the switch/outlet box to the bow where the light to be controlled by the switch, is located.
You will need to then connect a short piece of Black wire, about 8" long, from the outlet's brass colored screw (use the one without another wire connected to it, or double up with an existing wire, making sure they are both snug and secure). This should go to the BOTTOM of the light switch with the switch (look for "OFF" on the toggle, or see the metal strap for the proper orientation of the switch for determining which end is up!)
Now, the wires that go to the switched light: Take the white wire FROM the light and connect it to the white screw on the outlet. Now take the Black wire from the light location and connect it to the TOP of the light switch. Take the ground wire from the light location and connect it to the light switch AND over to the outlet ground. (If this is in a Metal box, you also have to attach the Ground wire to the metal box using a Green colored grounding screw, per Code requirements). As a Licensed Master Electrician, you should verify that your application meets the local requirements and codes, based on your location, as each part of the country has some special quirks to installations, based on their experiences. For instance, in Chicago, IL, you have to wrap electrical tape around all the device (outlets & switches, etc.) before they can be approved for installing into electrical boxes.
Please remember, there are several ways to accomplish the type of wiring you are looking to accomplish, and getting it done really depends on where your supply electricity is presently located (at the outlet/switch box or at the llight fixture, etc).
I would strongly suggest that you visit your local library and check out a Bacis Wiring Book, (or you can buy one at Home Depot or Lowes) so you better understand how to best wire your devices so they are done correctly, and most importantly, safely! If in doubt, ask a follow up quesions
You now have a constantly "live" outlet and have taken off power to control the switch that will operate your light fixture or device.
Here's some wiring drawings that might help you with your situation, as it covers 4 variations.
http://www.indepthinfo.com/wire-switch/
Again, if you have any doubts, please comment back and if possible, provide some photos of the electrical boxes you have and I'll try to help you figure it out!
Hope you find this Very Helpful and best regards!