Forms Needed

My ex has a possible job offer out of state. She has not worked in nearly 4 years and states that this move will not require me to travel that much farther than I am already for visitations. However, a check of a mapping software reveals that the total distance one way for visitation there would be nearly the same amount as an entire round trip as visitation exists now. What forms do I need to file with the court to keep her from moving my children out of state and would the court grant that even in the face of her having a job offer in another state. This move would seriously cut into my time with my children