Not wanting to start an argument but you said you think yours is a silky, but said she is registered. is she registered as a silky or a yorkie.
here is a very good site for information. Fell free to PM me if you want to.
Dog Breeding and Canine Reproduction by Debbie Jensen. Dog Breeding and Whelping guide for dog breeders.
The gestation period is 63 days. learn as much as you can before her due date.