lol ye i believe its a rather large job and i THINK (not positive) that you will need a compression test, someone else might be able to back me up on this??
you could do with a compresion test,to see if you have a cylinder leak..
but with it loosing water,overheating.and running rough..its not looking good..
Compression test should not be expensive. They just screw the attachment on the tester into each sparkplug hole, one at a time, to check each of the 4 cylinders. You can even buy a compresion tester and do it yourself - they don't cost a fortune.
compression test will show up any leaking valves etc so you will have to have the head off to sort that out. then check the head for cracks and warping. if you have never done anything like this before, leave it for someone who knows what they are doing. assembly needs camshaft locking tools to replace the cambelt correctly. They can cost £100 a set http://www.auto-tools.co.uk/s.php?p=9154
or just swap the engine,..there are plenty about in breakers yards.,compression testing is easy and cheap and can be done with the haed on,pressure checking for cracks can only be done with the head off the car.these are two different ways of checking the for compression/pressure.you could take your head off and get it pressure checked at it comes back ok ,..only to find out your bottom end/piston is cracked hence getting a compression test done first.
