Well, you've got an engaged audience, and you're telling them how to do something for free. I'd probably focus on related products or services. If they're on your page, you know a few things about them: they don't know how to transfer an iTunes library, and there's a good chance they just got a new computer. You might try affiliate programs for tutorials, must-have Mac software, utilities, online backup services, etc. Generally speaking, CPA makes more than PPC, and PPC, generally makes more than impression-based advertising. Do some A/B testing to see what works and what doesn't. With the traffic numbers like yours, you should know pretty quickly if something is working or not.

If you want to try more short-term, sleazeball tactics, you could always do paid linking, affiliate payout-based "ratings/reviews," popunders, zero-click redirects, etc. They work well on sites with short life spans, but really drag down sites over the long term.