Go to Mapo ... it's on Bloor Street near Christie, and easily accessible by public transit via the Christie subway station. That part of Toronto is known as Korea Town ... you'll figure it out when you get there :-)

Otherwise there are some great Korean places in North York, but it's a longer trek from downtown. Daldongnae, on Yonge Street a block or two south of Steeles, is pretty good. There are also some good Korean restaurants in the Kensington Market area but I don't know that area as well.

You're in the right place for good eats though. If nothing else, Toronto has an outstanding restaurant scene.