I am sorry for your loss of your little Tyler. It is never easy responding to posts like these and it seems there have been a few other posts as yours with others who are grieving too over their lost Yorkies.
Take time to heal your heart and to comfort you son. You will know inside when it is the right time to bring another Yorkie into your family's home. This is a time for healing, not for jumping right into researching new breeders, etc.
Keep the happy memories of Tyler close to your heart....