GreenCard renewal

我的green card renewal is in process, biometric has already been taken 4 weeks ago, but i haven't received the new card as of today, i need to travel outside the states in Jan 31 2007,
what should i do? (note: my green card expired in Jan 07 2007).

P/S: i do receive a letter from INS which indicates that my current status will be extended another year, i was told by someone that as long as i show evidence of my expired green card along with this letter to the custom officer, i will be fine. Is that true?

Thanks!!