Upgrade 3.7 to 3.8.2
 

I want to upgrade one of my forums to 3.8.2 from 3.7. I have a custom template that is really just an edit of colors and some table headings graphics changed. As well as red buttons.

What should I do to upgrade without losing what I have already, i.e, the buttons, table heading red graphics instead of blue like vb default has?