Don't know if bel air and impala are the same but any paint store that sells automotive paint should be able to mix and put paint in spray cans. English Color here can. They are all over Dallas.
gmpartsdirect.com shows to have one for $163.19 and says they are gm parts with gm warranty. Don't know anything about them. Look and make your own decision . Located in North Carolina. I have account with GM dealer and my cost is $188.01 List $250.68.