No heat - how to bleed the system?

[wwilme]

My '04 Mini (non-S) has no heat. It has NAV, thus no temp gauge so I have no idea how hot the car is running, but I do know the radiator fan comes on during extended idle, so I'm guessing the t-stat is not stuck open.
First the coolant was low (in the expansion tank) so I filled the radiator and tank and was squeezing the upper radiator elbow hose to feel for flow when it sprung a leak in my hand. Seems it had been wearing on a corner of the alternator. I then replaced it (at a ridiculous dealer cost of $45) and filled up again. I'm guessing it got some air in the system when I topped off the radiator, if it didn’t already have some in it. I have tried bleeding the system with the two bleeder screws (one just behind the elbow hose I replaced and one under and left of the battery on the hoses to the heater core), but have not been able to get the heat back. Fluid always come out, but it accompanied by bubbling – not sure if that is normal. Someone told me I should drop the lower radiator hose, drain all the coolant and start over with a re-fill. So what is the proper procedure for getting air out of the system? Is there a sequence for bleeding? engine off/on? heat off/on? I don’t want to drive it and blow the head gasket!