This happens to be one of my children's favorite lunches, and for my little one with the milk allergy we just use red pasta sauce on his noodles.
I really don't even measure my ingredients anymore and in fact I forgot to add garlic in this picture of the ingredients, but it is such an easy sauce that I really don't have to be exact in measurements.
My Alfredo Recipe:
1/4 cup real butter
1/4 package cream cheese
1/2 cup Parmesan or Parmesan and Romano Blend
1/4 - 1/2 cup milk (depending on desired consistancy)
2-3 cloves fresh pressed garlic (you can sub garlic powder)