USCIS had clearly mentioned in their press release that all applications received after 11th June will be rejected. I don't think they will reopen the window some time later this year. Usually, the rejected/winthdrawn petitions' count will be added to next year quota.
Excerpt from USCIS:
USCIS will reject petitions subject to the cap for H-1B specialty occupation workers seeking an employment start date in FY 2013 that are received after June 11, 2012.
H-1B Fiscal Year (FY) 2013 Cap Season