I have the same situation...but the schools I am gonna apply indicate that "please provide all original transcripts for those schools you've attended even though you only took several classes there.."... I also talk to admission admin and they suggest me to get the original transcript from my first university in China..
I think you might need to: 1) Go back to your undergrad school in US and ask you advisor to retrieve the copy of your transcript from your first university in China. (assuming you provided it to them when you came from China). 2). Contact your friends in your first university, send the scanned copy to them and ask them to MAKE EXACT THE SAME TRANSCRIPT YOU USED TO GET FROM THERE.
Worst case... if you cannot not get it... ask your undergrad school at US to provide a certificate of the truth of your grade from your first university....and communicate your situation with your MBA school's admin. They shhould understand.