Sorry I don't know how to add photos here, but in the photo shes wearing head phones

Without a picture I can't be much help.

From what I can see (its really hard to find a pic of her ears without her lobes covered by something), she doesn't seem to be stretched that large. Somewhere between 4g and 0g, I would guess. If you're talking about what seems to be her signature earring, I would think anywhere from a 8g onward stretch would be sufficient (though the wire looks like it miiiiiight be a 10g, actually) The ear wire is much smaller and thinner than the actual earring.

If you are going for her look specifically, you can always buy the earrings and then stretch to fit. Though I really would dissuade you from stretching if you only want that one look. Stretching your ears is a body modification that is pretty serious, and after a point cannot be reversed without surgery (and it should never be assumed that even a small stretch will correct itself, everyones body is different), and unless you really enjoy that look you might want to look into jewelry that assimilates the look of stretched ears without actually stretching your piercing out. However, if you want stretched ears and all that goes with it more power to you!

Oh those are afghanistan earrings. I've heard them mostly called "saw" earrings cuz of the little saw like teeth =) You can find reproductions online as well as old silver ones. Check out good ol' ebay.