Synthrapol will probably remove the black from the yellow. However, Synthrapol requires the use of *lots* of ***hot*** water to work, and sometimes it takes more than one treatment to work completely. I would wait until the quilt is quilted before doing this.
If you really feel you need to make sure the bleed comes out before quilting, then I would first machine baste the top to a muslin foundation to protect the seams from ravelling. I would use rubber gloves and hot water in a bath tub (or a large sink, if you have one) to give it the Synthrapol treatment.
Edit: I should add that I really do think that Synthrapol will remove the bleed easily. Even though you put the top in the dryer, heat probably did not set the stain; usually these dyes require chemical setting to become permanent.