If you want it RC you need a pc board and a controller. I personally used a zipzap micro rc car i had laying around and wired 2 AAA's to the battery wires on the circuit board and wired the servo to the motor wires on the circuit board. I then put the car controller in one of my pouches. Press forward(up) on the controller and the rf goes up, push reverse(down) and the rf goes down. It is'nt super fast going up and down but it aint slow either.
Total cost to me: FREE!!!
I had all the stuff laying around and a friend gave me a servo.
If you were to buy all but the servo which you said you already have, it will only cost you $20 for the rc car and another $1-2 for the battery case.
Beware:if you do this, wire no more than 2 aa's or aaa's the circuit board can only take a MAXIMUM of 4 volts. the 2 batterys provide a combined 3.
Or you could always buy a kit from 1 of the other board members.
Hope this helps.