check engine light

I have a 2001 plymouth neon and the check engine light is on, I have taken the car to advanced auto and had them run the codes and it is coming up P0420 and P0456. Does anyone know what these mean and how to fix it.

P0420 is catalyst below threshold.
P0456 is evaporator control incorrect purge flow.
Sounds loke 2 problems. A bad converter. My need to be replaced and a leak or problem with the evap.