Congratulations on the approval of your conditional permanent resident status. Based on my understanding that you just received your green card and have yet to travel outside the U.S., and that you will only remain abroad for 30 days, you do not need a reentry permit for your trip to Asia in December. You can reenter the U.S. with a current passport and your green card. You should apply for a reentry permit, however, if you intend to remain outside the U.S. for more than one year.