The one you have setup is for your store's back end. The one I am talking about is in addition and shows login screen before yoiu even reach
http://www.trafficbatch.com/cart/admin. It is done on a server level and you can probably very easily set it up from your hosting account, or ask your host about this, they will be able to help you or even do it for you. Buttons are using images. If you want to change the color without changing the images you have to edit the button template not to use images but css colors and if you don't know what you are doing the template can break very easily. You can also make new images with same size as the existing ones and just replace the existing images