There is a standard amount that airlines will compensate in case your suitcase is lost. It is listed in conditions of carriage, and if I remember correctly it is 1156 SDR. If you are wondering what SDR is, it is Special Drawing Rights, a currency equivalent defined by IMF. Currently 1 SDR is about 1,39 USD. Any value above that you will need to get from your own insurance.

That the status has not been updated for 6 days is a fairly bad sign, and I would give them a call to ask what is happening. Normally, they should be able to check if the suitcase was loaded at each airport, and at least tell you if it left Athens, and arrived in Rome, if not the current whereabouts.