Private Health insurance: information on minor and especially major.

I have the standard coverage for foreigners through my school. I'm looking for additional health insurance to cover minor, but especially major illnesses/injuries, etc..  Mainly I'm thinking about the big health issues like cancer, surgery, etc..

I want to make sure that the medical costs, ambulance costs, room charges, special testing costs, equipment, and any other darn thing that they charge for is covered to an acceptable degree.

I need to know the names of companies that provide this type of health insurance in Korea.  I'm not interested in combination coverages such as life insurance and health insurance.

Any help will be appreciated. I live in Pusan.

Thanks.