[windsonguk]

Sorry just got to add:
How many days into the season is your bitch?
There may still be time for a visit to the vets for his advise on a pregnancy, at this time, and measures in place to maybe prevent this one, that do not effect the planning of a mating in the future.
PLEASE think about what you are about to do.
With the best planning in the world, even for experienced breeders of many years nothing is ever guaranteed in producing a litter.
With no knowledge at all, your gonna struggle.

To answer your question duration of pregnancy is approx 62 days, however with multi matings the date will remain unknown.
Also do you work?
My last litter took up 2 months caring for her during her pegnancy - and requires correct nutritions, exercise, and signs to look for if problems should arise.
The experience of knowing what to do and when should the birth come into complications.
Then out of the 10 plus weeks of rearing, includes communicating with prospective new owners to determin if they are good enough and have enough knowledge to take on one of my puppies. Performing Home checks on them, and alot of having to say NO to people I don't find suitable.
Plus the endless nights of staying up with Dam and pups to ensure she doesnt lay on them. Preventing mastitis, bottle feeding, it's all endless.
Temperament testing the puppies, ENS, planning when vaccinate micro chip and how to get anything from a couple to 15 puppies to the vets!
Getting Dam back into shape after puppies to lead a normal life again.
My litters take 6 months of my life in care, a life time thereafter in support to their new owners, and years finding a suitable stud dog.
I don't wish to pop your bubble, but please consider your options and make them for the right reasons.
To breed is to better the breed.