I hope this isn't the first amount of research you have done because it sounds like your girl will have the puppies VERY soon. I would not leave her alone at this point and hopefully you have a mentor to help you along with the whelping. If not, please contact your vet and see if they will help with the delivery or if they can recommend someone close to you who is experienced in whelping toy dogs. Yorkies cannot or should not deliver on thier own. you will have to be 100 percent hands on in helping. this web site
Dog Breeding and Canine Reproduction by Debbie Jensen. Dog Breeding and Whelping guide for dog breeders. has a lot of information to help but is no substitute for an experienced whelper.