Car Hire in Greece

Can anyone point me in the direction of good, cheap car hire in Greece?
The plan is to arrive in Athens, spend a week island hopping, and then drive out to Lefkas for a week, then return to Athens for the flight home. So, we need a rental car - big enough for 2 adults, 2 children and a couple of cases, for 1 week. This is last week in May, first in June btw.
The plan is to arrive in Athens, spend a week island hopping, and then drive out to Lefkas for a week, then return to Athens for the flight home. So, we need a rental car - big enough for 2 adults, 2 children and a couple of cases, for 1 week. This is last week in May, first in June btw.