Pattern Problem

There is a quilt that I would LOVE to make, only problem is it uses a fabric that has stripes of color (Cascade by Karen Combs) and so you have to cut apart the stripes, but it also just tells you that you'll need 1 3/4 yards of the one thing, but that one thing has 4 colors in it. I just want to go to the store and get my own 4 shades of one color. Anybody know how I could figure out how much fabric I would need for each of the 4 parts?