720p display resolution is too big for tv

I recently got the kanex hdmi adapter to hook my mbp to my tv. The quality is superb and sound is good as well. However, the picture is slightly too big for my size of television. I had to select the 720p option so that my tv could recognize my computer and therefore, I cannot select any other option if I want my tv to recognize my computer via hdmi. Is there any possible way to still be able to hook my computer with my kanex adapter and still be able to fit the full picture on my tv screen?