L.S.
My advice to you is to let the child live and do not add to the confusion anymore than the situation already is.
You would not want her to live her teen years as you did yours, because of that confusion.
By law, she is theirs. I know it is hard my dear to accept that, but we have to live with our mistakes and current responsibilites.
Once your daughter becomes older she will natually gravitate to you if the relationship is postivive. Do everyone a favor, as Jesus loved us, so you must forgive and make your family whole. Why alienate your parents from your life and their grandchildren? Those people who helped you in your troubled years. Reestablish those bonds and see how the family benefits, you may get what you seek out of that love.