You can change the rocker cover yourself quite easily.
While it's off give it a scrub and paint it.
It's got to be 1 of the easier jobs to do on the engine.
remove the 8 nuts (10mm socket) , remove the rocker cover, remove the old gasket, clean surface where the gasket lays, lay new gasket down on surface, place rocker cover back on top, tighten nuts as much as possible with your fingers, then use a normal wrench to tighten them up a LITTLE bit more, then finish off with a torque wrench to tighten them up to 10nm (7.5lb/ft).
Obviously while the R/C is off clean it up and paint it if you want.
You may also want to use a rubber gasket instead of the crap cork gaskets, they are a little more than the cork ones but are much better, they are also normally a one piece gasket, rather than a gasket and two rubber seals.