One can discuss at length what wine to drink with foie gras but, at the risk of being controversial, I don't think a Sauternes goes at all well. Such a sweet wine is already too close to the sweet richness of the foie gras.
I suggest you try a dry white wine instead, which can bring out the flavour of the foie gras by contrasting with it. Why not a "Cotes du Jura blanc" (those from the Domaine Rolet in Arbois (France)
If you really prefer a sweet wine, try something less sweet than a Sauternes, like "Coteaux du Layon, Croix blanche" a wine from the Loire valley, (those made by Sylvie Termeau at Rochefort/Loire