project difficulties topic temperature know via GSM

HI to all this Thread reader

I wanna need help for my project .
It's quite intersting topic .
I'm instrumentation and control enginnering final sem student,making project.
The difficulties came my way are:
how to connect microcontroller (AT89C52) with temperature output.
how to start program for display temperature
Project Detail:
I have made temperature mesuring ckt with the use of IC KA331. its output will come out from pin no.3 in the form frequency.

help me for this part also sending messege via GSM to mobile which is connected to microcontroller