Getting another bird is not the answer – this will make her even less tame and eventually she won’t let you handle her at all. Female cockatiels are generally not as affectionate as the males. She sounds very typical and is not likely to change what she likes. Not all birds like to be petted or touched and again, this is pretty typical for a female cockatiel. Each bird does have their own personality and as the owner, you have to accept them for who they are. In this case she seems very sweet and has her way of showing it, but being petted or touched a lot is not what she likes. You can try to get a handraised male if you want a more affectionate bird, but he needs his own cage. Again if you cage them together they will not stay tame. And even if you get a male, there is no guarantee what his personality will be. All you can do is try to pick out a sweet baby that seems to like being handled a lot.
Thank you for asking Lafeber,