OMD! You need to get her to a vet and get established with one as being a Chihuahua mix, she will very likely have problems whelping on her own and will need an emergency C-section! This is not something you can find easily in the middle of the night and she will die, as well as the unborn puppies, if she can't whelp them on her own.
At the very least she needs an ultrasound NOW to determine how big they are and how likely she is able to get them out.
It takes anywhere from 58 to 65 days FROM THE DATE OF THE BREEDING, which I hope you wrote down, before they will have the babies.
Please, for her sake and the sake of the unborn puppies, get her to a vet NOW to get checked out.
I can't stress enough, she WILL DIE if she goes into labor and cannot get the puppies out and doesn't get into surgery within a couple of hours and it will not be a pretty death!!!

Toto, CD, RN, CGC answered on 12/31/12. Helpful? / 1