Does anybody know if there are any vineyards near by Lanouaille that we can visit and have lunch at?
There are very few vineyards that have commercial tours-- usually you just see a sign that says "Vin à vendre" (wine for sale) or "Degustation" (tasting) Pull in and they'll give you a tasting and tell you about their wines (it's considered good behavior to buy a bottle or two -- it's a free tasting, after all....)
Even fewer have anything even resembling a snack bar, and I know of not a single one that has a restaurant or cafe (there's probably one somewhere, but the point is that it's basically just not done)
Meals at vineyards in France are not a common occurrence. You just stop, as Sunshine says, where you see a Dégustation sign, taste a few things, buy a bottle or two, and move on. I would actually venture to say that, in France, if there's a vineyard serving meals, they're not too serious about the wine.
In all my long travels in France I have only come across one vineyard where wine production, restaurant and, as it happens, hotel, were all taken equally seriously and done well, and that was the Chateau de Pizay in the Beaujolais. There may well be a handful of others but I have never managed to identify them despite looking.