I came across PSS offering this course. You may want to contact them to enquire more. If need be, go down on any Friday evening and you get to meet instructors to ask them more. I feel their prices are reasonable and the instructors knowledgeable. They should get you off your feet learning in your pursuit in this field.
But if you are looking at an advance course, then it may be hard to find one with an overseas instructor. Note, too, that not all workshops are genuine out there in the freelance market as some are but scams. A proper school with premise might be more assuring if you are not familiar with people in this industry.
Also, why not start yourself by reading some professional guide books? You can find them from riceball (at adelphi basement 1), library, and larger bookstores.