You can’t find it anywhere. Vila Viniteca is one of the larger wine stores in Barcelona, and they own several buildings spread over the El Borne area. Inside their main building, you can find wines and liquors for all budgets, including the filthy rich. They have a very nice selection of French wines such as Petrus, which I’ll probably never try but still enjoy looking at.
Even if you can’t find what you’re looking for in the store, don’t despair! They still have a warehouse out of town which holds the bulk of their collection…