I put a 2.0 zetec into my 1.6 setec fiesta, but the same principal for what you are wanting to do. Basicly you have to use the sump/oil picup pipe from the 1.8, a 1.8 waterpump and use the 1.8 ancillary things like alternator bracket ect. It will all bolt up ok but you might need to adapt the plate that goes between the engine and gearbox, although i left mine as it was but this leaves a hole.

The above is how it is done on the fiesta, and i see no reason for it being any different on her car.

You can run it on the 1.8 ecu, as some poeple have run their 2.0's on the 1.6 ecu. You will need the 2.0 maf and throttle bodie btw. If you later decid to go for a 2.0 ecu, you will need one with the code, i think desk, dewy or deep.

Hope that helps