Apartment Project Completion Delayed - How to Handle It

[bangalorebalaji]

I have booked an apartment in the Month of Sep 2012 and the agreement is for 12 months to complete the project with clause of 18% penalty either side for delays. Now the project is delayed for 4 months, what all are the things I should be prepared myself before meeting with the builder for a discussion to compensate the delays. Did any you overcome this kind of situation in the past and how did you handled it.