There are a lot of factors to consider regarding your question. To begin, it will depend if paternity was ever established and if you adopted the child. If the latter then the biological father would have no rights to the child, however, if the former then you may be out of luck. If you feel the father is a danger to the child then you may have a shot at intervening...
You really do not have any rights regarding the child. However, if there is a danger in the biological father having custody of the minor child you could attempt to intercede on her behalf. I wish Ihad better information for you. Your best bet is to try and get along with the biological father and maybe he will let you continue to have a relationship with your step-daughter. I am sorry for your lose. Good luck.
What a difficult situation. I agree with my colleagues that you do not have any rights to a step child. If the biological father is not suitable, you may want to meet with an attorney to see if there is any possible claim that you can make; however, the biological father's rights will trump all others claiming any rights. Best of luck to you and I am sorry for your loss.
This answer is for general informational purposes only and should not be relied upon for your particular case nor is it intended as legal advice. I have not reviewed your case nor have I met with you and the answer to this question does not in any manner whatsoever establish an attorney/client relationship.