interfacing microphone to MCU to detect two tones

Hi

I need a simple circuit to interface a microphone with an MCU. I would like to detect just two tones (2khz and 2.5khz).

At first I thought that I could simply use an ADC connected directly to the MCU as in here
8051 microcontroller hardware interfacing tutorials -adc dac 0808 0804
However apparently this wont work since the microphone gives AC output.

Can anyone please kindly indicate how the circuit should be. Sorry but I am only a hobbyist and have only an amateur electronics background, so please try to be as specific as possible (indicating which components should be used clearly)

Thanks

The connection between mic and PIC chip in my project used a simple common emitter stage.
I opened the gate for a short period of time and read the value in timer 0