paintscratch.com offers single stage in a pen or small bottles (1 & 2 oz). They also list Pale Primrose, but with an expected disclaimer that the paint may not match since the car is so old. Kinda expensive for the amount of paint you get, but for less than $20 I doubt you could get it done any cheaper.
Some O'Reilly stores mix paint, but most don't....and I don't know if they do very small quantities.