You cant inject wondercards in gen 3 pkm vc games... The gba injects run in my knowledge in the ds mode and its pretty hard the save to extract or other things... The fact is:
If you play pokemon gba titles injected on your 3ds, its extremly hard to get on the save, maybe your pokemon are stuck on ghe game...
Maybe its better for you to play on an gba Emulator for the 3ds, with that you can edit your save on computer