I think a narrow binding as Zozee suggested would look better than a larger border. Love the colors. As far as quilting, have you considered doing somewhat of an echo quilting. Example: quilt at the intersection where your plum color joins with your lighter colors ... basicly following the shape of your center design. Perhaps stitch like this 2 to 3 rows apart all over the quilt. Your machine may not have enough throat space to do this easily.