Hi, you should always start a thread like this with size of engine you have!
Anyway you've got a 1.8 (120). if the car has dropped its coolant then I suggest that you have a look at all the various things that go wrong with the 4 cylinder engine;
- Head Gasket (Mayonnaise looking oil, when looking at the oil filler cap)
- Water Pump
- Inlet manifold gasket
- Rubber coolant hoses
As for the idle, then the 4 cylinder engines always sit at 1200 RPM when cold as this a feature on all cars until the cold start valve has shut off or when the coolant reaches a pre-determined temperature.
They dont sit bang on 1k RPM, they should normally sit around 850 +/- 100rpm