In reply to stp:
I don't know about public transport, sorry, we had a car. However, we went there last October and there wasn't much wind, loads of pop up tents on the campsite and we had a cheap decathlon tent which was just fine. Food, stock up in Cornudella, there is also decent food for reasonable prices in the campsite cafe, but there is nothing to buy in Siurana village. i would think it would be quite easy to hitch down to the village to restock, though, loads of climbers with cars about, we gave some a lift.
There is a cash machine. i would take some cash from home, get some more out of the machine if needed and pay by credit card in the wee supermarkets (best exchange rate normally). Hope this helps
Heike