Since it is hand stitched, it will have to be treated very carefully. It is very pretty. I doubt the beige has darkened that much over the years. I would be more tempted to finish it first then gently wash. If you don't think the fabrics are 100% cotton, you might try broadcloth which is a poly-cotton. You probably won't be able to match any of the colors exactly, but go for a blend or slightly deeper tone, especially for the border. Your background shade is usually a light colored fabric. Were there any scraps left that you could take with you to the fabric shop? if not, you'll have to take the quilt.