It seems there may be a problem with individual in your blog. This leads me to suspect your single.php file could be the culprit. I would quote check that page.
Is there a theme settings tab in admin section with the text in it? Other than checking for that I would make sure that I read all the theme’s help files, and then email the theme developer if you can’t figure it out.
Just install Firebug, and inspect the element that you are wanting to change. You can read up on the documentation and learn how to use it. Once you know the name of the element you want to change you can just apply the appropriate CSS. Glad to help!