How soon do i need to file my H1B extension?

Question

My h1b visa and I-94 is getting expired on 25th sept 2012. My new employer will file my h1b petition(premium) before 45 days of my visa expiry. In case if i will not get h1b approval before existing visa expiry. Is it valid to work with my new employer before getting H1 approval? 
How long i can work with my new employer before getting h1b approval?

Answer 1

If filed under Premium Processing you will get to know the decision in 15 calendar days and thus you don't need to worry about I-94 expiry. You may continue working with for your employer.

If your H1B extension is filed before your I-94 expiry, you can stay as long the petition is pending.