In the future, you are typically going to want to mash with about 1.4 qts/pound and then sparge with whatever volume will get you to your pre-boil volume, which should be about a gallon-gallon and a half more than what you want to go into the primary.
You should also look into another method of cooling the wort than snow, which tends to insulate rather than cool. It would probably work pretty well to throw some of that snow into a sink or tub full of cold water to bring down temps.
When you do figure out your gravity, here's a calculator
that will tell you how your gravity will change with added water.