Key codes for 95 fiesta ghia?

I have a ford fiesta 1.3 ghia n reg. I got two keys with it, red master and black main key with two locking buttons. Problem.... there were no batteries in main the key. Where do I go from here? The car only cost me £400 quid. I am also getting a smell of petrol from the rear and the tank is half full. It is not losing any fuel i.e no damp patches on the floor. Any help?