If you have a top-loading washer, you might try washing with the Synthrapol as others have recommended, but stop the washer before it drains and let it sit overnight. I read an article written by a woman who hand-dyes all her fabrics, and she did extensive testing to find the best way to release the dye particles from fabric, and it turns out she had the most success with simply letting the dyed fabric sit in water for 12 hours. After that, the fabrics were colorfast.
I think you may run a risk of having your dyes settle in some of the lighter colored fabrics, but hopefully using Synthrapol will minimize or eliminate this risk. Another alternative would be to separate the fabric that is bleeding from the rest of the quilt and make it colorfast, depending on how much ripping out that would be for you.
Whatever you decide, good luck and let us know what you did and how it turned out.
For anyone who is curious, here is a link to the article I'm talking about.
http://vickiwelsh.typepad.com/field_...d-fabrics.html