By the sounds of it, labour will be very soon for your dog. After seeing the discharge, you should check her rectal temperature twice a day. When her temperature drops from 101 to 98 degrees she will begin to deliver the puppies within the next 12-24 hours.
At this time she may go off her food and start to scrape at her bedding to prepare the nest for her puppies.
Generally dog's are well equipped to give birth without our help so just observe her in case she needs to go to the vet, but chances are she will be fine. Try to keep the family away if possible as too many spectators may upset her.
A greenish brown discharge suggests a placenta has separated, after this a puppy should be born within 2-4 hours.
