Is anyone related to or knows the surname of

Hi all, my name is Alethea Marios from Melbourne, Australia. I am desperately trying to find out anything about my family history, as my last name is apparently a nickname but I am unable to find out when it was changed and what the name previously was. My grandfather, Peter Marios was born in Diakofti in 1909 and landed in Sydney sometime in the 1920's i believe. He either came out with or met up with relatives im told who have the surnames of Aroney and Castrissios. I know his father's name was Nick, and his mother's name may have either been Stamatoula or Irene. I have not much more information than this as unfortunately the truth has been lost with those who know. Please help!