I'd like to know what's she saying o.o

That's not standard Japanese, is it?

With no prior knowledge of the Pokemon in question, I would guess that ミー is the sound it normally makes. If you take it as a pun on the English "me" it almost looks as if she's saying "Be thankful to me!" in some twisted way.

thats more or less it, and matches the way the pokemon acted in the movie

"Me" is sometimes used as a Japanese first person pronoun, by some manga characters and comedians.