I think it is 5 months of processing time. I just sent out I130 application yesterday for my parents to the same center. Please keep the forum updated when you receive new update.
I-130 Petition (Parents)
05/24/12: I-130 Sent via USPS Priority Mail
05/31/12: Received email notification from USCIS
08/06/12: I-130 Approved (email notification)
09/06/12: DS-3032 form & AOS payment invoice (email from NVC)
09/07/12: Status of AOS payment made online was changed to PAID
09/10/12: I-864 & DS-3032 sent via Fedex Standard Overnight