What can be done if a non-custodial parent is moving 300 miles away and now wants the whole summer and no school visits?

She only sees 8 years old every other weekend and usually drops her off early. Mother never asks to spend extra time. Now she lost her house and is moving 304 miles away and says she wants the whole summer holidays and breaks. Why does she think she can have that luxury? I love the summer with my child. It’s our fun time. Why should I have to give that up because she wants to be that far away? On top she wants me to drive half way. Do I have to? I don't even feel comfortable with my child going that far away. She keeps threatening she will take me back to court if I don't agree with her request. I told her to file the papers. What's going to happen? I offered her a full week once a month in the summer shared holidays and breaks but I will only drive an hour. Isn't she supposed to file or give notice she is moving. Can't I oppose?