Hi Heather, if you want someone who will propose a brief and transcreate, I recommend Tag Worldwide. Two friends of mine used to work there and their approach is solidly research based and culturally sound.
For a less expensive, more involved approach I can recommend Adexchange (in my sector) and Asian Absolute (they do more than just asian languages). Both need your collaboration or the client’s to create a brief.
Hope this helps — if it’s not far too late!
if you do decide to try any of them, it would be great to have your thoughts and impressions.