It's not worth it. Take it back. The end of the cabinet pictured does not have wood or wood veneer. It's a thin particle board or Masonite product which has a factory applied paper layer "picture" of wood grain. You will never get real wood to match. Use contact paper or just match some paint and touch it up.
There are actually people who specialize in this type of faux painting. Call around -- it may not cost that much to get someone to come out and paint woodgrain on that little area.