Digimon Battle Spirit, a trading card game, only features certain Digimon from the franchise. Gabumon is not included in this specific game.
You might be thinking of another Digimon game where Gabumon is available, such as Digimon World or Digimon Rumble Arena.
Could you please clarify which Digimon game you are referring to? I can then help you with obtaining Gabumon.