Business School Guides | Low GPA at graduate school

Hi,

I have 3.56 GPA from NYU undergrad.
I also enrolled in 'graduate certificate' at NYU program while working full-time.
Registered for one semester, 4 classes (12 credit, full-time) and got 2.57
I did overextend my self and wasn't really prepared for final exams.
All 4 classes I took were related to my field, which is real estate.

Does anyone know I need to put this 'graduate certificate' GPA on my application?
If so, how much will it hurt my overall qualification...?
I'm applying to Columbia
...

---