If you are using the default aero theme I can change that for you, using Windows Style Builder and post it here in a zip folder.
If you are using a custom theme you will need to ask the theme maker. It's not cool to change someone else work.
This will be a custom theme and you will need to do 1 of these 2 ways of Enabling custom themes for it to work.
Enabling Custom Themes - Windows 7
Theme - How to Apply Custom Themes
I will need the color(RBG would be great) and a name to call the theme.
Let me know.