Five-goal forward Ayew was dismissed for an elbow on Aaron Cresswell in Tuesday's 2-0 defeat at Upton Park and is now banned for three games.
To make matters worse for Villa, striker Libor Kozak has been ruled out for a month after it was revealed he has suffered a minor fracture to his ankle.
The Barclays Premier League's bottom club Villa only have Gabriel Agbonlahor and Scott Sinclair as available strikers for their crunch clash with Norwich on Saturday, and Garde admitted Ayew will be disciplined
"He came to my office the morning after the game and we had a long chat
Yes, he will be fined," he said.
"He regrets it, he apologised publicly, he apologised to me, the team and the fans
He behaves badly on the pitch but then he behaves the way he has to after that.
"It's an accumulation of frustration, a little bit during the game, but this frustration has grown in the previous weeks with the results and the way we were not winning games
For a long time he was the main threat for the opponent
"I wouldn't like it if we sum up Jordan from this stupid behaviour
I'm trying to understand why he did that and of course he has to learn from it
Your individual attitude can have a big impact on the collective."
Agbonlahor has not scored for almost a year while Sinclair's last league goal game in August and Villa must rely on the pair to claw the 10-point gap back to fourth-bottom Norwich and safety.
Rudy Gestede is also out with a hamstring injury and Garde confirmed Kozak, who has only made five appearances this season, is unlikely to return until next month
"Libor is suffering a little fracture on the ankle
He will be out for four weeks now," he said
"Rudy could be back for next weekend."
Ashley Westwood (calf) could return but Carlos Sanchez (hamstring) and Adama Traore (foot) remain out.
Source : PA