Hi there. God bless you!! I have been having the same problem and have just joined today so that I could get some info and support about this very topic! My situation is almost identical to yours. i have a 9 month old female who is still very inconsistent.She only weighs 3 pounds and I guess that adds to the difficulty. It sucks becuase I am afraid to take her to other people's homes. She sleeps with us as well, and is crated during the day. I think the advice about watching them every minute is vital and also REALLY challenging. I am the only person who has to go out in the rain or at night. But I sure hear about it when there is an accident!! I don't know where you are posting from, but i am in Toronto and dreading the winter cuz I don't know how I will get her to go out at all!!! Have you heard of anyone litter training Yorkies? 
Good luck and thanks for your post, 
 
 