Using Pic to listen to audio tones from car radar detector

So i have Uniden R1 radar detector. This unit as well as many others has an audio output port for external speaker. I would like to feed that output to a pic to read the different tones for the bands K/Ka/Laser. each band having a different tone. I will use a PIC 16F628A (16F877A if i need more ports).

Thanks.