You may purchase Olympic coins from authorized retailers of commemorative coins of precious metals. Following is the list of some of those retailers:

Beijing Kaiyuan Gold Coin
Address : Floor 12, Jinyu Building,100 Xi Sanhuan Bei Lu, Beijing 100037
Tel: 010-68727609

Direct Distribution Center of China Gold Coin Inc.
Address: No.25 Xiaoyun Road, Sanyuan Dong Qiao, Chaoyang District, Beijing 100027
Tel: 010-64640900

More retailers:
http://www.beijing2008.cn/21/47/column212044721.shtml


Source: China.org.cn