Hi, I'm a Graphic Designer but this may be useful:
http://www.jobsdb.com/HK/EN/V6HTML/J...Home/index.htm
click on: JobsDB Salary Index
Yes, also roughly work it out from what you were earning before/what you want now, taking into consideration differences with tax etc (see my thread on Good Interview Questions).
I have had feedback from companies that don't have work available but have been kind enough to have helped with answering these sorts of things.