you can try asking at the SPCA. our dog attended a group session there. she's also a rescue dog that was obviously a low ranking one when she was at the shelter, so was quite scared of the large boisterous retrievers & labs in the same session. the trainer (nicola) was very good with her (and in teaching us) and by the end of our sessions, our dog was not so scared anymore.
SPCA is a good recommendation. If you want "one-on-one" training the pet-sitter I've used for last 2 yrs is also an experienced dog trainer. You can contact him here http://www.wishyouwereherehk.com/.
