The paint code for your Buick is located on the SERVICE PARTS IDENTIFICATION sticker which is probably in the glove box or on the underside of the trunk lid. Your paint code will be on the bottom line of that sticker and will begin with BC/CC followed by a U and four digits or if it is a two tone color it will begin with BC/CC followed by a U and four digits and then an L followed by four digits. The BC/CC stands for base coat/clear coat, the U stands for upper color, the L (on two tone colors) stands for lower color, and the four digits following the U and L is the color code. Write down that entire paint code (something like BC/CC U 0000 or BC/CC U 0000 L 0000) and take it to an automotive paint store and they will mix a color match, someplace like Ditzler Automotive Paint stores or Finishmaster Automotive Paint stores. If there isn't one of those near you then the quickest way to locate a good automotive paint store is to call an auto body repair shop near you and ask them where they get their paints.