Hello mate

Right, 12.12 volts, the alternator ISN'T charging, and is proved by the fact of when u rev it the voltage goes down (i bet when u flick it off the battery voltage goes up aswell yeah?). This i am 99.9% sure will be the fact the battery light is not working. The alternator relies on the dash light to commence charging (if the bulb goes it won't charge), now you say you've changed the bulb, and all the connections are plugged in. That could suggest a wiring fault.

Firstly, are u sure the bulb u replaced works? If so try this: There should be a very thin wire going to the alter not (green in colour im led to believe, and should be obvious as the only other wire will be a thick red going to the starter), it should have a plug on it, unplug it, switch on the ignition and touch it on something connected to the body of the car (like the alternator body, or similar) if the bulb doesnt light and you are positive the bulb is good its a wiring fault.

Let me know how u get on or if u need any more help