L1 B and H1B confusion

[txh1b]

If your H1b was applied while you were outside the US, your H1b is NOT a COS and you can continue to work on L1.

[seagull]

Hi ,

It might be a common query but excuse me for the same. I wanted to have some clarity around the situation am in right now.
I work with company A and during the early part of the year , i was supposed to come to US on L1. at the same time company B applied for my H1 in April 08 and it got approved.
Meanwhile L1 processing from Company A worked out and i travelled to US in August 2008.
My prospective H1 employer (company B ) has not got back to me except that i have been given a EAC number which when searched on USCIS says approvals notice has been sent to address ( prob. company B address). All this has happened while i was in india and this is the first time i have travelled to US.
Now my I94 is stamped for 3 yrs with company A.
I wanted to know till when i can work with Company A. I know on OCT 1'2008 the H1 will become valid.
i would preferably would want to work with company A till atleast July 09 next year. Is it possible?
Am not sure about Change of Status (COS) as H1 was filed while am still in India. My Company B fellow doesnt know am in US yet.
Any suggestions on my state. Are my fears true abt necessarily needing to change to employer B by October? If so , what are the options i might have?
Please do help. Thanks in advance.