Hmmm... Panic room, interesting. So, this could be challenging. What you're trying to accomplish is rather simple and could be done without an electrician. However, if you can't access the top of the wall then I'm not sure how your going to fish the wire. You mentioned unfinished floor, can you pull it up to access the top wall plate? If so, you could do everything yourself.
Fortunately, you don't have a newer home with the firewall code requiring the center board inside the wall.
Basically you're going to need to purchase a remodel/old work double gang box, 1 standard outlet, 1 GFCI outlet, 1 double wall plate, 12/3 gauge wire and a 20 amp breaker.
Tools: drywall saw, wall fish pole, wire strippers, screwdriver, drill.
Find where you want the outlet, trace the gang box on the wall and cut it out with the drywall saw or utility knife.
From the room above, locate the top wall plate and drill a hole large enough for you're wire and wall fish pole. Make sure you're above your cut out. Tape the wire to the pole and fish it down to the square you cut out.
Feed the wire though the gang box and install the gang box. Cut about 6 inches of wire off. Wire the GFCI (hot/black to copper, neutral/white to silver, green to ground). Use the extra 6 inches you cut off and wire from the GFCI to the standard outlet. Screw in the outlets to the gang box and put the wall plate on.
Now, back in the panic/fish room... You're probably going to have to drill holes through the ceiling joists to run the wire to the attic. Once you've done that you'll need to run the wire to your breaker box and replace the floor in the panic/fish room.
At this point if you don't feel comfortable working in a breaker box, don't. Call an electrician. However, it's very simple, switch the main breaker off. Take the front panel off, run the wire into the box from the top, hook up the wire to the breaker and neutral and ground bar. You can use an existing breaker inside your box for reference.
I hope this helps and I am no way responsible if you kill yourself from electrocution. ;-)