I would add strips to top and bottom to lengthen it and then add a border all around to finish it off. Depending on the design you might add a top and bottom inside border made up of narrow stips to lengthen it. I believe just adding to top and bottom without a final border might make it look unfinished. I have done this by making a strip of diagonal strips reversed in the center to make a V. Adds a bit of creativity tp the quilt.