A few of those things sound fairly easy to fix yourself.
The whistling noise and engine revs moving on their own is almost certainly an air leak, somewhere in the inlet piping between the MAF sensor and the cylinder head, or a leaking vac pipe connected to the throttle body or inlet manifold. Should be able to find where exactly by spraying carb cleaner around with engine running. Where the spray causes the revs to change is where unmetered air is getting in.
For the cutting out while idling, mostly this can be sorted by reference to Grumpy's guide:
http://www.omegaowners.com/forum/YaBB.pl?num=1194007453Coolant loss you need to identify location, usually Heater Bypass Valve, rear of engine UK driver's side.
Possibly early-stage headgasket failure; shine a bright little torch down the spark-plug holes looking for coolant on a piston crown, a few hours after it's last been running.
Oil-burning behaviour may be trickier to sort, but fix the other things and see how you feel then.
