Shop Window - RPG Maker XP

Ok. It's my second request for help in just one day. I need to get some sleep! My question for you is:

How do I change the background of the default shop window where you can buy and sell items. I have an actual photo of the inside of a shop that i have scaned in. I would like to use that image as part of the shop window. The shop window is divided up into 4 sections. The top section is blank, the next section down on the left has the text "buy sell leave" section to the right has "gold" its the section below that I want to change the background on. leaving the other sections as default blue.
I have managed to insert a background image in the window but it pastes it into each section.

Once I have done that I will need to change the font colour to a darker colour as the image I want to use is quite light and the default font colour is white. I belive my answer lies in the script but where?

I tried to insert a screen capture to help explain my prob but couldnt even do that lol!
Please help me peeps
Many Thanks.

to change the colors/picture  it needs to be the window skin, to change where things are and stuff need a script.