(Input.mousePosition) in the PlayerMovent: How do I get the mouse to follow my ps3 controller?

I'm working on the survival shooter (tutorial), and I am trying to figure out how to substitute (Input.mousePosition) in the PlayerMovent script for something that will allow me to control the right stick on my ps3 controller (to control shooting direction). Is there a simple way to pass (Mouse X and Mouse Y ) to move my mouse, or is this more complicated than I'm expecting?

Either way, I would appreciate some help. I looked through a few answers, but as I tried each example I ran into more things that I'm not quite familiar with (that were also slightly different from what I was trying to accomplish)...starting to feel like I'm moving further away from the answer.