Apply I485 ASAP

According to new INS rules, after your I485 is filed for at least 180 days, you can switch to other company's similar jobs without sponsorship (Precondition: I140 has been approved.)
For your case: You filed I140 in June 2003, let's assume it WILL be approved on or before May 1, 2004 which is your laid-off time. And if you file your I485, including advanced parol and EAD, now(you should have your 140 receipt with the application) and assume you get your receipt date is: Dec. 1, 2003. Then after 6 months of Dec. 1, 2003, it will be May 1, 2004. After that date you can change to other company with similar position without sponsorship. This means you already have interim Green card. So you don't need the new company transfer H-1B for you. However, you have to renew your EAD card once per year until your I185 is finally approved.