@desrman and @wvBimmer3Series
To get the broken bit out, it depends on how much of it is still in the hose coupler. If you can (CAREFULLY) use a Dremel to cut a slot in the remaining plastic and use a flat head screwdriver to unscrew it. If Dremel is not available, you could heat up the same said flat heat screwdriver and try to melt a slot into that plastic piece and try to get unscrew it that way.
To bleed the cooling system you'll need to get some BMW coolant and distilled water (mixed 50/50) and search "cooling system bleed". NOTE: it will take about 30 minutes to do it correctly and it's beneficial if you elevate your car's frontend a bit to help with the bleeding.
Last edited by BimmersGarage; 12-30-2012 at 08:47 AM.