simple gsm project

[uydarp]

i wish to control a servo motor using a cellphone.
How it should work.
1. A call from a know phone number calls a sim900 circuit.
2. Microcontoller check if the call is from a know phone number, if yes call is answered and a password is expected, DTMF decoder is used to check the password
3. If the password is correct the servo motor turns 180 degrees n back to 0
degrees, finish!

i have made a working model using arduion UNO & icomsat gsm shield,

now i want to build the same circuit by manually connecting all the components instead of arduino n shield on a breadboard

How should i go about doing it? what all components will i need?

thanks in advance!