I would first start with some sort of hidden kill switch. This can be done with a $5 relay and a little imagination. Some "dealer installed" anti-theft devices are just that. You can start the car with a simple toggle switch or perhaps an accessory such as activating the flash-to-pass option while starting. Older VW cars will not allow the vehicle to start unless the seatbelt is connected. This can also be duplicated with a relay.
Another thing you can do for about another $5 is go to Radio Shack and get a 12 volt blinking LED. Drill a hole and mount the LED in a very visable spot, say to the right of the headlight switch. Then connect the negative wire (usually black) to the pink wire in the ignition harness and connect the positive wire (usually red) to the red wire in the ignition harness. This will make the LED blink whenever you turn the ignition off. A $5 "alarm"
Next, I would find a way to cover the broken column. This can look very inviting to a theif as most of the hard work is already done for them. There are aftermarket reinforcing devices available for GM columns. I'd guess that these would exceed $50 though.