I second using a vex controller, they work very well as an inexpensive FM reciever as well as a programmable controller if that's a need too.
Personally,
I like to use an HPC explorer development kit from microchip.. It works very well and is much less expensive than a robot controller if youre handy with C programming. You just make up a progam on one HPC for the OI pannel that reads in analog voltages and some digital input, some output if you want, and packages it into a string.
Then, the recieving end just has to take the analog/digital inputs and make them into pwms or just simply copy the digital in to and out.
For wireless between the two, i like to use a
MaxStream data modem. And for range... the
Xtend modem has a range of 40miles line of sight with no FCC license needed, 256bit encryption and internal data packetization.
Just hook up RS-232/485 or near any interface of your choice to the modems, and bingo, wireless data. These can also be used in a network mode if you need to communicate with multiple devices.
Good luck!
-Q