You have a couple of options.
1. If you have the factory ford locking lugnuts you can go to the ford dealer and have them taken off....I think there are only a handfull of different patterns...and they will have the correct key to take them off.
2. The other option is to have your locking lugs taken off and then get new ones. It depends on what type of wheel you have though. I had lost my lug key when I had my stock bullit wheels. The lugnuts on those wheels are out in the open, so I just took the car to a local tire shop and had them removed. There is a tool used to get them off. It looks like a large deep socket, but on the inside there is a sharp reverse threaded cut. It is made of very hard metal and it will cut into and grip your locking lug and remove it. If you have the type of wheels that have resessed lugnuts, like cobra R type wheels, then I dont think there would be enough side clearence to use the lugnut removal tool.