Go to "Settings" at the top right of whichever page you're on, then to "Edit Avatar" under the "My Settings" panel on the left. The 3D models will be under the "Pokémon X & Y" category, while the Sugimori artworks will be under the "Official Sugimori Art" category.
Glad to see you've already got most of the Pokemon's XY sprites up already. Hopefully we'll have all of them up by the start of 2014.
I'm doing River Vivillon right now, it's my native Vivillon pattern.