Can i stay with H1 extention receipt number, even after 6yrs completion


I am in little weird situation to understand, I am with company A and my 6yrs is completing in June, i applied GC with company B in Dec 2012 and wating for the labour approval so i can transfer later.

As i am still with company A and my I-94 expiration is May 1st, i applied for H1 extention and got the receipt number.

so my question is can i wait/or use the waiting period (<=180days after h1 extention with company A) to get GC labor apporval for company B or should i leave the country before end of June as my 6yrs is completing.

thanks a lot for the help.

can someone please answer my question?