GSM based electricity theft identification

I am working on a project which is a GSM based electricity theft identification!
I am using SIM900A GSM module,a MAX232 chip(to interface GSM module) an ATMEL AT89S52 MCU,16×2 LCD, TTP223 touch sensor and a buzzer.
The main theme of this project is: if anyone tries to tamper the energy meter(in my case if someone touches the touch sensor) then the microcontroller receives the i/p sent by the touch sensor and then the buzzer starts to buzz and the MCU sends the GSM module the action to send a message stating " theft detected" to the predefined mobile no.(hard coded) and showing the same message in LCD.
i am stuck with the coding section! anyone up for rescue? i have attached the .jpg file of the circuit diagram.

You should start with something, We will help you reach to the end. So write something.. see tutorial section for LCD interfacing, serial communication etc. Ask questions when you get stuck.