Most dog trainers love dogs so much, it just kills them when this happens. We’ve had a few on the forum volunteer their time to people, but a trainer can only do so much with the dog, it's really up to the owner. Dog trainers train the people on the correct training methods, and the owner must follow through. Of course the owner always has loads of excuses why it didn't work, and I imagine it gets hard to hear the same things over and over with the result being a dog's death.
Many people seem to think that dogs are replaceable and if one doesn't work out, they can just put it down,
I'm not at all saying you are like this, but this does happen, and sometimes the gruffness you might see in trainer is a way to not become too emotionally involved in cases. I doubt if you will need a personal trainer for a Yorkie, aggression isn't a problem with this breed, but you can make any dog aggressive, if you don't handle him properly.
There are many books out there on training, and so much information is available for free. Pet Stores often have pet training classes, but they are more social classes, and the information you receive can be found in most books. I think the first step in training should be having a through knowledge of "potty training", if this goes wrong, and punishment or force is used, the results may be an aggressive or overly anxious dog.
Here is a link to housebrecking your dog.
Free House Training for Puppies and Adult Dogs - No More Accidents Starting Today! I also suggest Cesar Millan the dog whisper, for really understanding the way a dog "thinks."
Welcome to Cesar Millan's Official Web Site If you can't view his programs on the discovery channel, you can rent his whole series of DVDs from Net Flix for an extremely affordable price.