Upgrade my website

I created a website using the Wordpress theme "Origin" which i use to enhance a twitter quiz that I devised.
Having no previous experience of web design, I feel that the site could be made have a more professional feel to it.
The main purpose of the site is to help businesses who sponsor my twitter quizzes, to advertise their brand. (I also get most of my sponsors trending on twitter each night it is played).

Looking forward to feedback and ideas from web designers who know what they are doing (unlike me! :) )