Theft Deterrent System

I just got a 2003 Cavalier Sadan can I just go out and buy remotes. Then how do I program them. The car came with the Theft Deterrent System but the dealer tole me I had to get the LS model for the alarm to work but under standard equipent it list the Theft Deterrent System.

Please Help

Thanks

i have a theft system on my 96 cav, its not an arlarm though, if someone sticks anything beisdes a key in the ignition the brakes and steering wheel will lock up

MY 2002 cavy came with laser-cut serial numbers in the windows....
...... Im assuming thats what you dealer meant by theft-deturant....