FIrst of all I just want to say eww . . . Really? With pooing on the furniture and on your bed. She is definatly trying to tell you something and to get someones attention. Please read my training tips on how to teach your dog to alert you when it's potty time... it's not too late to teach her this method. But it will take more than just yourself to accomplish it and it works !!!
Training Tips - Dawn's Yorkies
I would also suggest trying Umbilical Cord training with her. Especially if she's running off and doing her business where she cant be seen. You have to watch her like a hawk !! This training allows you to have her in your sights at all times and doesn't give her the opportunity to run off after a nap, meal or play time and go potty in the house. She'll be right there by your side for you to get her out side to go. Than praise and treat her with a Cheerio or something small that wont make her too full or spoil her meals. Umbilical cord training works great for all types of training. Even to show her her boundaries in the house and out in the yard.
Also, schedule her trips out to potty to coincide with her with her feeding and naps. Dogs take a while to do their business it dont matter if its hot, cold, rain, snow or shine. You cant just expect them to go out and right back in and if they do that usually means that they didn't go poo. They may pee sudden but to poo they have to be in the right place at the right time with the right scent. Usually when they smell theirs or another dogs scent is when they will go. So cleaning the areas in your home that she has gone pee or poo will definitely Help. Than start fresh.... get into the habit of taking her out after she wakes from a nap, after her meals (
free feeding would not be a good idea) and after she has been playing or resting. You cant do this alone in your situation. You are going to need help form other family member if you going to get her trained.
I wish you luck and hope that you find something, anything that works !