Hi I am new here and I am from Malaysia.
To the thread starter, you can visit Luna Bar or Sky Bar in the city, worth visiting to get a night view of KL.
For shopping, go to Mid Valley or One Utama (this is in Petaling Jaya).
For food, I will always tell my friends to visit Penang, which is north of KL approximately 2 hours drive.
Good luck and enjoy your trip to Malaysia