Adopting our niece with special needs

Our niece had a stroke before she was born and is mostly blind in one eye and she is also very under weight and has neurological problems that have delayed her development. We are about to be going to court to contest an adoption by a lady who isn’t taking care of her the right way. I was just looking for advice on contesting an adoption and also taking care of a child who needs more attention. I had custody of her while she was 3 months old until about 6 months she is now 1 1/2 years old.