I am glad that they are starting to get along better, but now it sounds as if the new cat is trying to boss the older cat around, if she is even trying to chase her away. I imagine the older cat has had her feelings hurt, since she has been the only cat for quite a while now. I think it would help to give her more special attention, and also do feed her separately, so you know she is getting to eat her food and the younger cat is not taking it away from her. Maybe she should even have a separate place she can sleep and not be worrying about the younger cat bothering her. I think they will eventually start getting along together, it is just going to take time and effort.