Did you make
any btc transactions yourself near the time (within a couple of days) of these transactions?
Yes i did, but 4 days before, the 27th, was my last (own) transaction (outwards), since then only receiving, untill that moment on the 31st, which i wasn't..
So the money is on this adress: 1FmMasfuEE6wtpzdWiVnDynfJ5tyyVbhP3
and there is "only" 0.56 BTC. That does not sound like a hacker to me. They would have moved the money and switched adresses several times. Do you have backups of your wallet(s)?