Why didn't you apply for EAD at Local INS office to begin with ? I thought when you have Local INS office in your city then you can apply for EAD and AP at Local INS office, atleast it is like that in Cincinnati, OH. My H1B expires at end of Nov but I still haven't applied for my EAD because when I inquired with Local INS office they told me it takes only 3-4 weeks to get EAD here. So I still have some time.
But I think if its 90 days and your EAD still pending Approval at service center then you may go to Local INS Office and get the Interim EAD.
Which service center did did you apply for EAD ?
HTS