Ok, I'll try to answer this.
Given that this was according to Icelandic regulation (I have to take that point as I don't know the Greek law, but we can assume some point of fairness through both), and the transitional phase would start in February, you would be allowed to finish the training you started according to national requirements, given you started before February and were done with it before the end of the transitional phase. Any training started after the beginning of February would have to be according to JAR-FCL, type ratings too, even if you had a national licence.
So given above and that you want to get your multi pilot type rating before the summer, you should start now. But keep in mind that you might not be as attractive as the next fellow, if you are applying for a job, if you don't have any MCC but he does!
I have to emphasise to you that you will have to familiarize yourself with the Greek law or move to Iceland. Read the regulations for your country and ask the Greek CAA (if they are ok to talk to).
deTrix