I second lapping the valves yourself, but while you have the valves out I would re-condition them and clean up the combustion chambers, as well as replace the valve stem seals. You can re-condition the valves by chucking them up in a hand drill and spinning them through a piece of scotch brite in your other hand (at least that's what I did)
Make sure to look up a how-to on re shimming the head, there's a few good ones out there if you search. That's the most important step in making sure you don't toss rocker arms again.
As far as the cyl with low compression goes, I'd imagine that was caused by the intake valves not opening and thus not letting any air into the cylinder to be compressed. Obviously you run some risk by not tearing the entire bottom end down and checking the rings, but I'd imagine you're probably safe just to rework the head and call it a day.
I'll add some pictures of before and after re-conditioning valves in a second...
