I know this will not solve your problem for this quilt, but I think that you must have taken much more than 1/4" seams when sewing the strips together. I counted 32 rows in the quilt, and that is what you should have when you are done. Each strip should finish at 2". 2" x 32 strips = 64". Double check your seams for the next one!
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Otherwise, I think the idea of adding more strips to the top and/or bottom would solve your problem. Hope you can find the same fabric or close. It's a very pretty combination.