Electret microphone into iMac 3.5mm TRRS headphone jack amplification
That particular electret has a pretty low sensitivity. You might simplify your life by using a mic with a higher sensitivity, or better yet, one with adjustable gain built in. This mic from Knowles has adjustable gain. This app note has a pretty good explanation of how to convert a three wire mic into a 2 wire mic (with Vdd and data sharing the same line).