From what you know of her history - did she actually go after the cats at the previous owner or just stare? Mine, especially Ciara, do the same thing with my grandson's cat (cat is living with us at the moment). But they don't do anything to hurt the cat. And if she does try to play with the cat and gets too mouthy I can usually call her off.
I take it you want to get her to stop staring when you give her a command? I don't think you can really "cure" the fascination.
I think I'd try really intense work on "watch me" as a start.
Caleb (aka Caleb-Moose)
Ciara(aka Ciara Belle, Black Devil)
RIP Aodhán, Rica, Max, Kelly - gone but never forgotten - forever in my heart