You can renew your visa 6 months in advance. Consult an attorney as if you are not in a true management position as opposed to doing daily tasks it will be difficult to renew.
You can file an extension request up to 6 months prior to the expiration of your current status. Chances for success depend on facts that must be reviewed by an immigration attorney for an assessment of the case.
Before it expires.
You should retain an experienced immigration lawyer to review all the facts, advise you, and handle the case. You can find one through http://www.ailalawyer.com.
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.