Exercise... I'm all for
Exercise... I'm all for it!
If I understand you correctly, you'll need to use this color in your footer code, which is the green from above: #8EAB01
You'll need to use this as the background color in #footer, and also for several other DIV's inside #footer. After that you'll probably need to change the text color in those areas so that it looks good with the new color.
Since this is in Wordpress, you can do this in the Admin interface. If you have the current WP version, look in Appearance... Editor. You should find what you need to edit in style.css and possibly also in footer.php.