I have enlarged a small quilt. I added backing, batting and borders to a crib quilt. I made the batting about 1/2 inch smaller than the backing and border material. Then sewed it onto each side of my quilt, just like you would on a "quilt as you go" project. Then to complete my border pattern (because the quilt had already been quilted) I just sewed straight lines about 3/4 inches apart up and down the new border section. Then added my binding and it looked great.