Qualifications
Technically, there are no formal educational requirements for television commercial directors (source). But you need to get yourself some graphic design, film technique, and computer skills somehow, and college is a pretty good place to start. The majority of directors and producers in the television commercial industry went to liberal arts schools, where they often majored in film, theater, or advertising. Degrees in audio and visual technology can be particularly useful.
But regardless of whatever formal education and vocational training you pursue, be prepared to pay your dues as a groveling production assistant. You've got to start somewhere. And somewhere, in your case, is going to be at the very, very bottom.