Need some info from susan

Hi need some help regarding temporarary skilled migrant 485 subclass visa.  I have been assigned to a case officer on 31 jan but Iam on bridging b right now in India came for business trip for a company in Australia do I need to go back in the specified period or can i stay here and complete my work and go back to Australia . I have given all the required docs to them my schedule is till march 26 can I ask for permission to delay or can u suggest something I can't spend more money for travelling