Not on rte until January, BBC3 or online, try any streaming or torrent website and you'll find them uploaded in line with when they are being shown in the US.
BBC2 started showing MM season 4 3 weeks ago, 4 episodes a week. The last episode is on this week. This is their last season with it; SKY Atlantic will have season 5. I assume this means RTE will not have it after season 4.