Mark,
you should go to Radar RC.
http://www.radarrc.com/index_eng.php
Take the MTR train to Ngau Tau Kok station (fairly short ride from Mongkok). See map:
http://www.radarrc.com/retailShopLoc...LocationEN.htm
They have a fantastic selection of Futaba radios and parts, as well as OS (if you fly props) and other product lines.
Fly safe,
- Thore