Your website uses a Movable Type template, over 100 of which can be found at The Style Archive. The template selected for you is further customized to best match the image and persona of your company.
The template, or look-and-feel, of your website is controlled by a Cascading Style Sheet. Commonly called a style sheet or CSS file, this file contains instructions to your browser on how to display your site, from colors to images and layout.
If you are not so handy with code, then you'll need some help if you want to make site modifications on the style sheet. The location and filename of your style sheet are dependent on what theme is being used, but the base directory is:
wwwroot/cgi-bin/mt/mt-static/themes
Another design note: your site is set up with a default page extension of .shtml. What that means is that you can use Server Side Includes (SSI), such that code common to multiple pages can be contained and edited in a single text file. This is very useful for the inclusion of site-wide advertisements, for instance. See the top ad banner on OjaiNews.com for an example. A reference for SSI can be found here.
You or your designer will need FTP access. If you have not already received it, please contact Tribal Core, and we will set you right up.