Hmmm without jumping to any conclusions the oil thing if you switch to a thicker weight will help consumption.
The coolant is more of a worry. Is there any leaks?
Ie once you move the car away is there a pool left behind or a few drips?
Might be one of the clips has come undone or is not longer sealing.
Well thats what I hope it is.
Otherwise the water is going somewhere - espcailly with a dodgy idle would suggest something more sinister like head gasket is on the way out. But you'll notice this as the temperture guage will obviously shoot up very quickly. But I am not going to jump to take conclusion.
Alfa 166 2.0 Twinnie - LPG and a few trick performance parts