Here is a very good thread that has a lot of the information you need.
http://www.yorkietalk.com/forums/bre...-research.html
Please take your time and read through the information and then feel free to ask any other questions you might have.
Here is a good website on whelping puppies:
Whelping Dogs
I recommend feeding her a good quality food. I feed my mommas Canidae and dry Chicken Soup puppy food. I would not start the calcium supplement until after the pups are born.