Consider your pattern "the general idea" or a "guide" and now make lemonade from your "lemon"--Once you begin to think about it in a different way that the picture, you'll come up with an arrangement that works, altho it may be quite different than the original pattern. Just be creative and don't feel the finished quilt has to be exactly like the picture on the kit.
You will have a great quilt. Don't forget to show us.
I agree with others, if you'd show us what you have done so far, some of these creative ladies would have ideas on how to use them for a beautiful top. Also, remember your SIL hasn't seen the picture, so she will have no idea. Besides she will be getting an original and that is the greatest.