Actually, there are tons of companies that can do a good job with this...
Around here the two main places to go are an outfit called Paint Specialties
and good ol' NAPA Auto Parts. Both places can "read" a paint chip and mix to
match, then put it in a spray can for you. The main difference is Paint
Specialties costs about twice as much.
So, just grab the yellow pages and call around.
No matter what they tell you, the aerosol paint has a VERY limited shelf life!
I'd suggest that you use it immediately after buying it.