How do you change the type,color etc of those buttons.
You can't. You will have to create a custom GUI with custom GUI buttons on it. (See this tracker entry (http://www.adventuregamestudio.co.uk/tracker.php?action=detail&id=408).)
You will probably need the QuitGame function. Look it up in the manual.
I think you can only affect the text font of the buttons. Since they use the normal font, simply import another font and put
SetNormalFont(THENUMBEROFTHEFONTYOUJUSTIMPORTED);
into your game_start function (menu "Script" -> "game_start").
Ok thanks I'll see what I can do. I may be back. :)