H1B under cap exemption

Hi,

My employed applied H1b (COS) cap exempt under premium processing.

Current status as below:(From USCIS)

Acceptance

On August 23, 2014, we received this I129 PETITION FOR A NONIMMIGRANT WORKER and we e-mailed you a notice describing how we will process your case.

Now i am in US on B2. My I-94 is going to be expire on 9th Sept 2014.

What can i do now if i am not get any decision before 9th Sept 2014