At a loss where to get some War of 1812 or Napoleonic gear? Look no further than MilitaryHeritage.com. These guys from Canada have it covered, and more. The selection of firearms is very impressive, and at reasonable prices to boot. They have matchlocks to doglocks to flintlocks, and from what I can tell is their strong point.
They have some uniform pieces from the Napoleonic eras, which they seem to cater to the most. But if you do F&I War, Revolutionary War or even Early Colonial reenacting, MilitaryHeritage.com is still a great resource.