If you still have the original hand book for the car, it should have a key code in it. Take this to a good locksmiths (cheaper than main dealer) and they should be able to cut you a new key and programme it also.
The key code is not a problem - as pwhittaker says - any locksmith can cut the key. This will open the doors and petrol cap. If it is a PATS key (has a red flash on top) - It has a chip inside that is part of the immobiliser system. The last answer was WRONG in that a locksmith can programme the key - unless he has an OASIS (ford type computer) you will need to get it programmed at a ford main dealer. OR you could find the red key which lets you program other keys.