Pomeranian

"We had a thanksgiving guest show up with their 3 dogs yesterday. They explained that they are feeling extra "attached" because less than 2 weeks ago they lost a dog to parvo. OMG! One of the dogs they brought wasn't vaccinated until after they lost the other- this dog was not showing any symptoms and was very playful appearing healthy. We have 2 dogs and one of them isnt vaccinated. What should we do? Its the weekend and we can't contact our local vet."