I've read a lot about something called Super Mario Galaxy Save. Could someone please tell me what this is. Thank you

You have to have Super Mario Galaxy and saved that game at least once. That's all.

A Galaxy save simply allows you to unlock Rosalina easier and faster than completing all Mirror cups 1 starred.

So its a completely separate game which I would have to buy?

Yup. But if I'm honest, it's a shame if you don't have it.

The save isn't a game, think of it as a save file stored into the Wii. Mario Kart Wii has one too. But you have to have the Super Mario Galaxy save file stored to your Wii to have that save file.

Yes it is a seperate game but just rent the game or borrow a friend's copy play it for an hour or so then unlock Rosa that way and say your self 40 dollars in the process

Thanks. I might do that.

you only need to start the game one time to get Rosalina...

Someone brought over Galaxy and played it for five minutes on my Wii, now i have Rosalina, sweet......

You dont know what super mario galaxy is? Thats a shame as its (in my opinion) the best wii game