Usually on outlets controlled by a switch, only one of the 2 plugs is controlled by the switch, the other is always hot. Also typically the outlets controlled by the switch are installed upside down, so you know which one are controlled.
Since one of the plugs is always hot, and the other is controlled by the switch, there will be 2 hot wires, a separate one to each plug.
***Verify that both plugs on the outlet are controlled be a single breaker 99% sure that they will be*******
After determining which plug is switched and which one isn't, you'll know which hot wire you want to use. (disconnect and tape the switched wire)
You'll need to buy a new outlet. In order to have seperate hots, the existing plug will have had a connecting brass brigde (between the top and bottom plugs on each side, by the screws) clipped off.
With the new plug, connect the hot, neutral and ground. You only need to connect each wire once and it will serve both the top and bottom. DONT FORGET THE GROUND!!
Assuming both plugs in the outlet were served by a single breaker (probably more than one outlet on a breaker) the total connected load on that breaker shouldn't have changed and you'll be OK.
Its really a lot easier than I make it sound.........good luck!
