I'm Italian, and my maternal grandfather was a "numismatist trader" (
commerciante di numismatica). He made pretty good money in the '70s, when the field had a short-lived boom, but in short: don't ever do it for the money, the field is full of sharks that will happily part you from much-more-modern currency. Valuations are often pulled from thin air, even the most official-looking ones, and things that are supposed to be rare because of age (say, a Roman coin) end up being anything but - because they were coined in massive numbers.
As for supporting grave robbers: that's unlikely, unless you actually live in the Middle East (where the practice is still relatively easy to carry out). You can easily look at it in the opposite way: a lot of those countries will never have the interest or money to properly look after minor artefacts; so you might as well try to preserve things for them.
In terms of what to do with hoards like this one, it really depends on laws of the country - afaik in Italy they can't be sold to the public, they are automatically State property and that's it.