Recovering lost address contacts

I am using an iMac with OS 10.7.5. We, unfortunately, have not used a back up system such as Time Machine, but after this experience, we will!

My son attempted to back up my daughter's iPhone on our iMac. After the back up, we discovered that our Address Book contacts had been replaced with hers. None of our original contacts existed in the whole address book nor in any of the sub groups. I did some research to see if I could figure it out and discovered several solutions. Several of them were above my technical understanding and ability and the others just didn't work.

I have found the Metadata files and attempted several ways of getting them back into the Address Book but no success. The files show sizes of 175 to 395 bytes, so I'm guessing there is data in there. When I tried to import the files either through the actual file or after putting it on the desk top, the Address Book does not read them.

Any help would be much appreciated!