I live in Rio Rancho, a NW suburb of Albuquerque. I will start checking the papers. If you can email me a flyer of sorts, I'll post it in the pet stores I go to. I'll also give my vet a call as he knows a lot of Yorkie people. I'm not 100% sure where Tanoan is, but I believe it's NE, toward the mountain. If it's the neighborhood I'm thinking of, it's a gated community in a pretty high $$ area.
I would think going to the neighborhood and posting signs as well as talking to as many people as possible. Possibly checking out all the pet stores/vets, etc w/ in a certain radius. If she simply 'took off', I would think she would have been nabbed by someone in a fairly close area. The area is pretty populated, so I wouldn't guess that coyotes & bears would be a concern as they are in some areas.
The major newspaper here is at
www.abqjournal.com I think they put the lost/found on the net and that they can be accessed for free.
I'm not familiar with a yorkie rescue group here, but a major 'no kill' shelter/rescue is watermelon ranch. A good friend volunteers for them and has been checking for yorkies for over a year hoping to find one thru them, so I'm fairly certain they haven't seen her.
Might there have been any paperwork regarding the pup in your brothers files - vet records, breeder bill of sale, pictures, registrations, etc. Any of those might help a bit in the search. Does the vet know where the dog might have ever been boarded?
Offering a reward is good, but, in this area, from what I've seen, I'm not sure it would help. There is a family that has been offering a $1500 reward for the return of their Yorkie Male for almost 2 years, as well as another similar for a dalmation. It seems some animals just 'disappear' here. Not good.
Let me know what I can do.
You might also contact a local TV station. I know channel 4 - KOBTV has a very 'pet friendly' meteorologist who brings his dogs on the air at least once a week. Maybe you could elicit some help there.