Nope, sorry. You can only download PokeTransfer by accessing Pokemon Bank, which means paying the money for it.
>No, that is not possible. Poké Transporter is companion software that works together with Pokémon Bank to transfer Pokémon from your copies of Pokémon Black, Pokémon White, Pokémon Black 2, and Pokémon White 2 to your own private Boxes hosted online through the Pokémon Bank service. After downloading Pokémon Bank, you can download Poké Transporter for no charge. - Pokemon Bank FAQ