You can also find the Transmute Mineral Ore spell in Halted Steam Camp, just behind Whiterun, that can turn Iron Ore into Silver Ore when cast. Silver Ingots are a little harder to track down, though most general vendors or Smiths will sell them from time to time.
Vampire Dust can be obtained by defeating any vampire enemy, though can also be bought from several Alchemy vendors, including Arcadia in Whiterun. Deathbell Flowers can be obtained by delivering Farengar's Frost Salts to Arcadia in Whiterun, while being found in the wild around Morthal fairly consistently.
Thankfully, only one of the ingredients needed is hard to find, while the others can all be found relatively easily.
