Too late for the OP, but, if I was you, I wouldn't start from there. There are only two trains westward from Ponferrada each day, one at 06:15, which you have already missed, taking 4h 18m to SdC, including a bus service between Monforte de Lemos and Ourense, and the other at 18:36 (I took it two days ago - as always, it was an hour late) arriving in SdC not long before midnight.
There are no direct buses that I'm aware of, although ALSA offers a service via A Coruna at 08:25 and 19:00, taking 3h 46m. Hope you made it somehow!