As your dog's temperature is 98.3 her time is very near. Keep taking her temp as it will probably fluctuate for a while but once it stays consistently low the puppies are definitely ready to arrive!
I'm guessing you have a box ready for her and have maybe introduced her to it already. Its a good idea to settle her into it when you can tell the time is close.Generally she should be okay to give birth alone but be there for her in case she does need help. Have the number of your vet at hand just in case there is a problem, though unless the father was bigger than her, I don't foresee any.
If the father was bigger than her, she may require an emergency c-section as I know you wouldn't want anything to happen to her or the pups.
C-sections are expensive things unfortunately (around $2000) so I hope it won't come to that.
Best wishes to your dog; I am sure she will be a lovely mother. My problem would be parting with the puppies :-)