If you file for an extension of your B2 status before the end of August, you will not accrue unlawful presence unless it is denied. If you stay more than 6 months after the date on your I-94 card, you will be subject to the 3 year bar to reentry. If you overstay by only 5 months, you will not be subject to the 3 year bar, but a Consular official can use that to deny a future visa.
Answered on Aug 23rd, 2011 at 11:22 AM