That is very pretty! I think I'd do a white, then a print border. Maybe a solid, marble or solid looking binding. I'd probably have to lay out some fabrics to get an idea of how big to make the borders. If you don't want to go too big, you could do a narrow inner border and wider outer border. If you didn't prewash, you might want to consider that it could shrink and end up a little smaller than you planned.