Well you can only buy tickets a max 10 months in advance. So at the earliest, you're looking at buying the tickets in december. Generally tickets are cheapest when they first go on sale, however there can be some pretty phenomenal seat sales that come out getting you a sweet deal. It's always a gamble...generally you'd have to wait until about mid sept for the deals to start really popping out though, since sept is still really at the end of the high season. I'd probably take the gamble and wait, but that's just me. I think generally there can be some pretty phenomenal seat sales that come up, and when you find one that seems good jump on it.
As for the month, at this point in my life I would be content with just sticking to Italy for a month (just because italy is wonderful and I'm starting to slow down in my travel style) but if you haven't traveled much I'd definitely want to see more...I say 3 weeks in italy, 1 week touring around other places....