I am likewise looking for the Greek Fathers (the 'main ones' like Origen, Cyril of Alexandria, Athanasius, John Chrysostom, Basil, Gregory et al.) in Koine.
I have found an eMule file share of Patrologia Graeca, but it's hopeless so far. Since eMule takes forever to actually work.
I also have the Apostolic Fathers in Koine Greek, that I got off of the Christian Classics Ethereal Library.