lost original RC of my car? How to proceed to get another copy? Do I need to lodge an FIR first?

First lodge FIR with local police station. Apply for duplicate RC on official application along with the copy of FIR to the regional transport office where you registered your vehicle. You have to pay the required fee also, If you have photocopy of the original RC, the thing will be little easy to get duplicate RC

You had not mentined your country, so got receiving different answers. In India also Motor Whicle Act and Rules are different in all States. In Gujarat you are required to bring copy of FIR first as per latest rules.

no need for fir. some electronic shops carry controllers except that you have to know the frequency like 27, or 40 mhz or what and how many channels. i seem to recall seeing them in radioshack's catalog, and their store/counter personnel can help you identify your needs