Apply for Work Permit with already existing Residence Permit/Spouse Visa

Hi all, I've been living in Shanghai since May with my husband and my daughter. I've a Residence Permit/Spouse one (valid till May 2014) and would like to apply for a Work Permit. Where can I do that? Do I have to go back to Europe (I'm German) or to HK? Which documents do I need? How lomg does it take and which costs I should expect? Thanks for hints in advance!

Best regards
Miriam