Star Online said the stray bullet pierced her intestines in nine places, resulting in her having to undergo two surgeries at the University Malaya Medical Centre.
Two policewomen were seen visiting the girl at 1.30pm today, but left half an hour later.
The gunman, who was with an accomplice on a motorcycle, struck when the real estate agent had just had lunch with her children and a maid.
The woman, Renyce Wong Siew Ling, 32, was behind the wheel of her Toyota Vellfire when the gunman fired five shots, killing her on the spot.
Her husband runs a cosmetics business.
No arrests have been made so far.