Large Breed Diets

I made a big mistake on Thursday, I purchased a bag of Pedigree Large Breed Dog Food, along with our normal brand, Purina's Lamb & Rice for Large Breed dogs. I normally buy the Purina at the grocery store, but they have been out of stock of late, so I thought maybe I should "try" something new. The Pedigree bag had a picture of a Great Dane, so I thought it would be safe.
My poor "Cleo", she is a 4year old Great Dane. She has been throwing up and has diarrea now for 3 days, the other dogs seem just fine. I've been giving her ice cubes (it's 97 today!), and I have her in the air conditioning. She's still eating, and her nose is cold and wet, so I'm not that worried, but I am concerned.
I was wondering if anyone has heard of this receipe for an animals upset stomach....I've used it for years, and I was wondering, what do other Dane owners feed? Should I buy her some PetTabs vitamins? Here's the receipe:
Boil hamburger in water until cooked, strain.
Add cooked rice and cottage cheese, stir and serve!
I need a home remedy, my husband doesn't think a vet is neccessary at this time. Thanks in advance for any advice.