I got US visa Oct 2003 and I came to US only on May 2005I worked for consulting company A.

My Client company B offered me Job on July 2007 and I worked for them till June 2010.

I have the approved I140 from Company B with a PD Nov 2008 (EB2 India.)

I got laid off from B.I got a new client and joined consulting company C.

I have the H1B extended only for a year till Oct 2011. Company C mentioned about AC21 to retain my PD whenthey submitted my papers for H1 Transfer.

Company C did say that they will process my green card.
Company C haven't filed for Labor Certificate and I-140.
what are my options to get extension on H1B? Can I change the employer
and will I be loosing my PD in that case?

Please advice on my next steps as well.

I appreciate your time and input.