Howdy, TCP global has a color chip library, just enter the year and model and you can see the original chip sheets with the codes. They show the backs of the sheets which have good info too, neat reference source. They can mix up the paint from any of the chips but the smallest quantity is a quart which would probably do the whole roof.
Car paint online has lots of original colors and an easy search to find your color by code or make/year. They can make a 2oz touch-up size but they don't have every color for every model/year.
Allan
http://www.tcpglobal.com/autocolorlibrary/
http://www.carpaintonline.com/index.php