My hand-out says; Clear liquids the first three days (has list of approved clear liquids)Day 4 begin w/ one serving of a Protein supplement to be mixed w/ skim or 1% milk. You may also include low fat milk daily. Goal is to include 48 - 64 ounces daily, milk should be included in this total.

Does that mean I can drink up to 64 oz's of protein supplement or I should drink 1 serving of the supplement and the rest milk?

Should I keep drinking lots of Clear Liquids w/ the 64 oz's of supplements/milk

It means you can have one Protein supplement that is prepared with milk. Just one.

You should also have 48-64oz of Fluid daily. That amount should include the milk used to make your protein supplement. This should include a lot of Water and other clear liquids.