Advice for neglected cat?

My aunt was recently given a cat that is so beautiful and loving, but also so scared and nervous! This cat is about 1 years old and was neglected and kept in a cage for long periods of time. Despite all this she is still loving, and will let you pet her all day if you can catch her, but she will not approach you and will avoid everyone in the house. She also has a problem where her claws come out because she's afraid, but you can tell she doesn't want to hurt you and is just frightened. How do I help this cat become less afraid? Thanks, GOD bless!