To reenter the US, you will need to have an H-1B visa stamp. The earliest that you can enter the US on that Visa stamp is September 20.
J Charles Ferrari Eng & Nishimura 213.622.2255 The statement above is general in nature and does not constitute legal advice, as not all the facts are known. You should retain an attorney to review all the facts specific to your case in order to receive advise specific to your case. The statement above does not create an attorney/client relationship. Answers on Avvo can only be general ones, as specific answers would require knowledge of all the facts. As such, they may or may not apply to the question.
If you are approved for H1b, you cannot get the H1b visa until September 1, 2013. If you are married, your spouse can get an H4.
The above is intended only as general information, and does not constitute legal advice. You must speak with an attorney to discuss your individual case.