You absolutely should *not* use Retayne at this point. Retayne should be used only on yardage, before it is ever pieced into a quilt. Once a bleeding fabric is in a quilt, washing with Retayne can permanently set bleeds.
Your best bet is to wait until the quilt is finished, then wash with Synthrapol in hot water in either a top-loading home washing machine or a large front-loading machine at the laundromat. Synthrapol will suspend unset dye particles in the water so they can be rinsed away instead of settling into other fabrics. It requires hot water and lots of it (so the dye is sufficiently dispersed in the water). I would do this before giving the quilt away, and advise the recipient to use color catchers afterwards (or even give it two washings in Synthrapol before giving the quilt away).