Questions regarding I-485 intervew

[pk81]

I have received notice that as of 01/08/2016 my I-485 application is ready to be scheduled for an interview. I have still not received information about interview date and time. Do you know how long it takes for the interview to be scheduled and how many days in advance will I receive communication about the interview date ? Also, in case the interview goes satisfactorily, does the GC get approved at the same time?

My application is filed under EB1 category. I-140 was approved on 05/27/2015. I-485 was originally received by USCIS on 09/28/2015, it has since been transferred twice to different processing centers, and is currently at NBC.

Thanks