You can file as soon as you get back. But they will have a record/you will need to disclose the rejection. In the rejection notice there are instructions as to when you need to leave the country. You may consult with an Immigration attorney to see what your options are.
Att. number 917-885-2261 This advice does not create an attorney client relationship. No specific legal advice may be offered by the lawyer until a conflicts check is undertaken. Information sent through a web form or via email may not be treated as confidential. Please accept my apologies for spelling mistakes. Law Office of Alena Shautsova , New York Immigration Attorney http://www.shautsova.com Blog: http://www.russianspeakinglawyerny.com
You need to return to India to get a new H-1B visa. Don't worry about the one month overstay.
(213) 394-4554 x0 Mr. Shusterman is a former INS Trial Attorney (1976-82) with over 35 years of immigration experience. His response to your question is general in nature, as not all the facts are known to him. You should retain an attorney experienced in immigration law to review all the facts in your case in order to receive advice specific to your case. Mr. Shusterman's statement above does not create an attorney/client relationship.