Is she completely emptying her bladder? If she can come back inside and still pee she must not. Do you just let her out in a yard or do you take her for a walk? Maybe she needs a little more time outside to get it all out. I've heard of other yorkies on here peeing like 5 times before they're actually done. She has no infections right? And since you're feeding her on a schedule, does she poop on a schedule?
http://www.dreamydoodles.com/puppies...sebreaking.pdf
You might want to get that book How To Housebreak Your Dog in 7 Days and use that schedule to get things together. That pdf can get you started. I really liked the schedule because it allows no free time until after the potty. It seems as though she hasn't earned the privilege to roam around the whole house. Especially since you can't always keep an eye on her.
Sorry you're going through this. It must be frustrating for you and your husband, but with some patience and consistency you definitely can make it through!.