Whats the best Camera and lens for high res Interior photography?

I've been asked to produce a book on interior design. I would like to supply my own photographs for its content. These will need to be very high res and very good quality to be printable in a large book format. I have basic photography skills and a decent cannon digital (35mm) camera. I dont want to spend too much money but I think I will need at least a better lens and tripod etc, any suggestions?