I would just manually set up the prices using the calendar function. Airbnb's calendar is much better than other booking websites (cough Stayz/Homeaway) and you can just select a clump of dates and enter in a price, perhaps adding a bit extra for weekends. It might take 20 minutes but it's well worth the effort. That way, you can also specialise your price to maximise profits for high demand dates (public holiday, special event date, etc)