Have you thought about checking online for Yorkie meetups near your area? It is a great way to introduce your pup to other dogs and people. Just walk around for awhile until everyone feels comfortable. My friend's Yorkie likes the people rather than the dogs at times. I'm sure both of you would have a good time.
If your dog is still afraid try it again. My dog was bitten by a Silky that was off leash last year at a garden center. She is so afraid of other dogs now except for her one friend. I have been taking her to the meet-ups. She is slowly getting better. It will take time for her. I have to be patient. Check it out..