*Do not wash your quilt top. Its seams are too fragile to sustain the pulling they would suffer, especially while wet. *If it is dusty, gently use a vacuum cleaner hand tool with the end covered with a piece of muslin or a white handkerchief.
*If the outer border has not been hemmed, then you could stay-stitch it (within 1/4 inch of the edge) by machine, to strengthen it, and prevent stretching and pulling.
*Examine all the seams. If any are pulling loose, then carefully re-stitch them by hand.
* Are any parts wearing through? (possibly rayon) then you could applique a reproduction-print piece over the orginal without interfering with the stitching. This works as an invisible repair job.
You have a treasure, which will be even better when it is completed, and can be shown proudly.