You cannot use Poké Transporter to directly transfer Pokémon to your Pokémon X andPokémon Y games from any previous titles aside from Pokémon Black, Pokémon White, Pokémon Black 2, or Pokémon White 2.
However, here are some steps you can follow to reach your goal.
Use the GBA Game Card slot on a Nintendo DS Lite or Nintendo DS to transfer Pokémon fromPokémon Ruby, Pokémon Sapphire, Pokémon Emerald, Pokémon FireRed, and Pokémon LeafGreen to an area called the Pal Park in Pokémon Diamond, Pokémon Pearl, Pokémon Platinum, Pokémon HeartGold, or Pokémon SoulSilver.
Then, using two systems from the Nintendo DS family, transfer your Pokémon from Pokémon Diamond, Pokémon Pearl, Pokémon Platinum, Pokémon HeartGold, or Pokémon SoulSilver toPokémon Black, Pokémon White, Pokémon Black 2, or Pokémon White 2 using the Poké Transfer facility that exists within those games.
As someone who has done these weird things to transfer pokemon over the years, it just seems sort of crazy to see Nintendo write it out and say “yeah this is the intended, official way of doing this, so have fun buying 15 DS’s.”