PIC12F675 Design Suggestions - Frequency to Frequency

Hello, I need some design ideas here for making a simple - low cost PIC controlled adjustable Frequency to Frequency converter.

Input frequency will be a square wave 5vdc. ranging from 0khz to 20khz. I need to process the input freq and increase/decrease the output frequency by 1% increments up to 255%.

Frequency output will be selected by 8 switches, (i.e. switch setting 00001001 would yeild 17%)

If input was 1khz

At 1% output would be 10hz
At 100% output would be 1khz
At 200% output would be 2khz

Thanks for any pointers.

My idea I have is that I will use a Frequency to Voltage converter. Then run the Vout from that into my PIC12F75 which has a 10-bit A/D internally. There I can read the freq and modify it per switches and out put a new frequency using the onboard timer/counter?

Good?