[Aken]

For the blue edge on the navbar, that table uses the Table Border class in your Main CSS area. Look for the box that says Table Border and .tborder, and edit that as you see fit.

The background colors for those two boxes near the bottom can be changed using the Table Footer area (.tfoot) in your Main CSS area also.

To use an image as a background, the following format should be used:

#5C7099 url(images/gradients/gradient_thead.gif) repeat-x top left

#5C7099 defines the color underneath the image.
url(images/gradients/gradient_thead.gif) defines the location of the image.
repeat-x specifies that the image should repeat horizontally.
top left defines that the background should start at the top left corner.