Miyuki-MiamotoFeatured By OwnerJul 6, 2012Hobbyist General Artist
The character she is cosplaying is Yoko Littner (sometimes written as 'Ritona', because that's how the Japanese pronounce it.) from the anime 'Tengen Toppa Gurren Lagann'. It's well worth a watch. Hope that clears things up for you.
This is the best representation of a real life Yoko you'll see. (But of course that is merely my opinion.) One can only hope to be as good as her.