my sister started a new game when i had deoxys,hoho,lugia, and mew2
You know what, there's two ways to get you happy again:
1. Grab your game (which is now your sisters) use an action replay to get all your pokemon back again
OR
2. *Punch your sister. (for this to work she'll have to be smaller)
*I know it's a bit radical but hey, she did reck your game.