Anyone knows how to extend a Business Visa?

My business visa will expire on May 29, 2013 and it is 1 month already. I want to extend it up to 3 months. Is there anyone here who can tell me the legal process of extending the visa?  And how much?

The company that is sponsoring you will have to arrange this, as they did for the original visa, as it would (I assume) mean that they would have to justify why you need an extension and/or why the RP has not yet been processed as well as confirming that you are still employed for them.