Tell her to post an ad on
Petfinder.com: Adopt a pet and help an animal shelter rescue a puppy or kitten. in the lost and found section of the classifieds, just in case the owners happen to look there.
Also, when she places ads, make sure she leaves out identifying information (such as breed of dog) and make sure the owners provide that when they call. Too many people might call and lie saying its their yorkie.