Someone posted a request ages ago for info on where to eat and stay in Corsica in October. Sorry this is so late, but I haven't read the message boards for a while - anyway, you may find this useful.
We went to Corsica in May for three weeks, and found lots of good places to eat. My favourite was just North of L'Ile Rousse, called the Auberge A Tesa. It's a lovely place to stay over night too, the rooms are very nice and they do a bargain half board package. It's hidden in gorgeous countryside down a little lane off the N197, they have peacocks and a stream with ducks - very idyllic. The food is what I would describe as modern traditional Corsican cooking, and was excellent. I think we paid a total of £64 for the two of us - Bed, breakfast and evening meal - including a five course meal, all the wine you want and an aperitif.
We went to the Roche Rouge (after a recommendation from this board), and it was lovely - especially having an evening drink on the terrace, and they serve drinks with the best olives I have ever tasted. I was not so impressed with the food though - I got the feeling that they are relying a bit too much on the spectacular view from the dining room. It was good, but not as special as it should be at the prices.
Along with the A Tesa, another memorable place to eat was a kind of transport cafe just off the N193 South of the Town Bastia, but North of Bastia Airport. It's called Chez Flora, and is just off the main road on the road to St Florent. It's basic, and the two times we went there we were the only people who weren't lorry drivers or policemen on their dinner break, but the food was amazing. I think the set menu was 10 Euros for three courses and wine. There is no choice, and it isn't written down. The first time we had chickpea salad with thick slices of smoked duck breast on it, followed by fillets of red mullet in a gorgeous saffron sauce and new potatoes. The second time it was a large plateful of crudites - including tuna and rice, followed by pork chops and asparagus. I can't remember the puddings, but the wine was better than most places with menus that cheap. It was as good as the food we get in mauch fancier and much more expensive places in Britain.
We had a surprisingly good meal in "A Piazzetta" (I think - it's in the little square between the harbour and the main road) in Erbalunga.
We had a very good meal in Corte, which, whilst Corsican, was a bit different from the food we'd had elsewhere, so made a nice change. The restaurant was called Le Paglia Orba.
In St Florent, the best meal we had was at the Ind'e Lucia.
One more place worth seeking out is in a village called Valle-di-Rostino off the N193 in the hills in Castagniccia. The place is called Stella di Rustino, and it is run by a mad Spanish Basque, who has two mad dogs! He specialises in really good traditional Corsican food, and is very proud of feeding his customers well. Make sure you are hungry when you go - the cooking is great and very filling.
I hope this all helps, and that you eat well