How do I change the main template color theme?
This is not really complex, as long as your are familiar with css, though it will require some time. All you have to do is change some colors, gradients and replacement images.
You may either edit the main files, or create a separate color stylesheet with your custom style – the second option is mandatory if you want to be able to use further theme upgrades.
As a beginning, you’ll find here the detailled list of styles that need to be changed to affect the whole template color theme: http://pastebin.com/vybsXyhs.
I suggest you begin by editing the template PSD and use the hue/saturation tool to find the exact tint you want, then pick the colors and report them to your color stylesheet. For gradients, you can use this tool to easily create the correct syntax and download replacement images for older browsers.