[Greg Reid]

motor29, imagine a thinwalled pipe with threads on the inside. Imagine another slightly smaller thinwalled pipe with threads on the outside and a nut threaded onto the end. Imagine screwing one into the other until the nut on the smaller inside tube is tight against the larger, outside tube.
That's what you basically have with the inner protruding through from the front of the dash and the outer tightened against the back of the dash. The plastic part that you cracked is like the nut in our example and is captured against the front of the dash to help keep the inner tube from pulling through the back as the two tubes are tightened together.
Since the plastic 'LIGHTER' ring is not a nut but simply slips on, you must reach the assy from the back and unscrew the 'outer tube'.
Breaking the plastic may not help you as I'm not sure the inner tube will back through the hole even with the plastic out of the way.
Hold the inner tube stable by sticking a finger in from the front. Reach behind the dash and turn the outer tube clockwise (viewing from your perspective) to unscrew it. The inner tube will come out towards you, the outer tube will come off towards the engine compartment.