Only one DS/3DS? You can still get your Pokemon onto your game, without using a rom.
1. Get a flash cart, download savegame manager, smallftp and Pokegen.
2. Install savegame manager onto your flash cart. Install and set up smallftp. (Google will help you set them up)
3. Use savegame manager to export your save to your PC via FTP.
4. Open the .sav via Pokegen and add your Pokemon.
5.Import the .sav using savegame manager back into the retail cart.
Bingo, You have your Pokemon. Takes a bit longer but it is still possible.
That only works with a normal ds/ds lite doesn't it?