Typography in advertising is the main thing I want to focus on

I want to research typography and colour in advertising and how it can effects consumers to buy a product.
You can't measure the impact of typography on a consumer. A bit easier approach is to understand typography as an equivalent of persuasive speech and deconstruct the goals that the authors (probably) wanted to reach. Anyway, there are no easy and clear methods; qualitative research needs a lot of time and effort.

Do you think this is enough to go on or do you think I should focus on an area of advertising, gender or product?
Definetly, you should focus yourself on certain area (not only on the above mentioned, but for example some design patterns, like titles or claims).

Last year, at one of our schools, a group of students wanted to start very similar program. As the school has marketing/menagement profile, they were quiet well prepared to design and manage the research. Inspite of good will, and after long and difficult discussion with the dean, they had to quit the program and change the theme, as the dissertation wouldn't fill the expectations of broadly understood, academic and "scientifical" objectivity.