Ok, so you could just use the same pattern for the top, but handstitch some tulle into it, so it sticks out. Tulle is super cheap and pretty easy to gather that way.
As far as the skirt, just make it longer than required in the pattern, and then fold and gather it- kind of like a bubble skirt. Then sew a skirt or even just a small piece of maroon fabric to the inside, and then make a sash sort of thing.
Now that I look at it, this dress looks like a drop waisted dress, so maybe this pattern would work better:
Again, you would just lengthen the skirt and omit all of the lacey stuff. Another plus with this dress is that it will show you how to make the sash. If you need any help, PM me and I will do the best I can
By the way, I was going to make that dress over the summer but I never got around to it. Maybe I will still attempt it. Good luck on your project!