how do i hook up my co2?

Can i rig a normal co2 regulator (lets say one used for beverage despencing) to a timer?

No, you need one with a solenoid so that the flow can be stopped and started by electrical power. You might be able to find a solenoid and plumb it to your regulator, but it might be just as cheap to find a used one on eBay. I bought mine in like new condition for $60.