Urgent help needed L1 to H1 and fresh H1

[Sri]

I am working in A company on L1 and applied for L1 to H1. As of now the status is showing as processing.

And I have applied fresh H1 from another company B and it is approved.

Please let me know do I need to start workin g from oct 1 2006 from company B or I can work as long as I can with my current comapny A.

Is my L1 status is chenged to H1 automatically from Oct 2006 with new H1?
Do I need to inform to my company A?

I have personal issues, because of that I can not start immediately with new H1 with company B. ( I need to wait 2-3 months time)

Please help me what I need to do..

-regards
sri