First, I am assuming that your current attorney is also court appointed being that you want to request a "new court appointed lawyer"?  You will need to contact New York State's Bar Association and inform them that your current court appointed attorney is not representing you appropriately due to the fact that the grandmother is missing court ordered visitation and denying your rights to visit your child.  This is considered contempt of court and it has to be reported by your attorney via filing contempt of court pleadings with the court.  Your attorney is failing to do so due to the fact that court appointed attorneys receive very little pay for their work.  This is unethical and needs to be reported to the Bar Association.  A new attorney will be appointed to you and the grandmothers contempt of court behavior will be documented thus helping you in your case!  It is imperative that you follow through with contacting the New York State Bar Association if you want to make a change.  I hope this helps...........