A couple of things: The directions on my Retayne bottle say to use HOT water and after treatment, to only use a cool water wash. I put hot water in my sink and thoroughly wet suspect fabric. I can see how much colour is coming out--if any. Yes, it can be a pain with a large piece, but it gives me piece of mind.
For the finished item that has bled, try washing again using Synthrapol (sp?) It keeps the dye particles suspended in the water, so that they don't reattach to the fabric. Remove from the washer immediately and if not using a dryer, keep the fabric in one layer--no folding when wet.