To use the microphone as an input, you need to adjust the incoming signal level to the sensitivity of the microphone and put a capacitor in series to block the DC component introduced by most microphone inputs. The capacitor C2 is usually not needed, it is intended to remove noice.

Here are some examples of receiver circuits:

Using the UPM thermometer as RF receiver for the 433.92MHz band

An RF receiver for the 433.92MHz band by Walter Krämbring

A generic high power 433.92MHz transceiver using an Auriel devices by Walter Krämbring