Which international conversation organization has the giant panda as its emblem?
The World Wide Fund For Nature. (WWF)
You can't. You probably wouldn't want to anyway - they are highly endangered, and to purchase one would be thoroughly unethical. However, if you want to sponsor a giant panda, you can do that through an organization such as Pandas International, or perhaps contact a zoo that has a panda and ask about sponsoring their panda.