How do I make this paint match?
Paint fades.

It is extremely hard to get an exact match on any paint after a few months.  The best solution is to paint a whole section (try ending at the edge of a window or door) or even a whole wall.

An even better approach is to cut out a small patch of the now faded wall to be matched (you can patch and paint it later when you repaint) and take it in to the paint store for a computer scan match. 

You still should paint a whole section as described above, but the joint will be even less noticable.