Maybe this link will help figure out what color your have. The paint code itself is printed on the sticker on the drivers door edge. It will say PNT:xxx The xxx is the paint code.
2008 Chrysler PT Cruiser Colors Available
You can order paint touch-up from the dealer, also most auto stores have touch-ups but they might not have the 2008 colors. They usually have them for older cars, but you can try.