If this is your first experience with black powder shooting, you may want to consider a single shot black powder rifle or pistol first. They are less complicated and more forgiving. And you may find it more entertaining to load, cap, shoot then repeat ---- rather than load, load, load, load, load, load -- grease, grease, grease, grease, grease, grease -- cap, cap, cap, cap, cap, cap, then shoot, shoot, shoot, shoot, shoot, shoot - then repeat. Sounds silly, but you actually feel like you spend more time shooting and less time loading with a single shot gun.
The revolver you describe sounds like one made by Conneticutt (sp) Valley Arms (CVA) - a .44 caliber brass frame model they called an 1861 Colt. Similar to the 1860 Army. These were actually Itialian made - but don't know by whom.
Around here, Academy Sports and even Wal-Mart carries balls, caps, measures, etc. Don't recall if they carry black powder - but several local gun shops do. If you look around a bit, I'm sure you will find several sources of black powder stuff. A lot of bow hunting shops also cater to black powder shooters (that whole primitive hunting thing).
In pistols, make sure you get FFF (Triple F) black powder or equivilent. Never use modern smokless powders in black powder guns - they can blow the gun up. The F's refer to how finely the powder is ground. The lower the F - typically the longer the barrel and greater amount of powder to be used. You should get a powder measure for consistancy of loads. Start with about 10 grains or so & work up. Not so much that you can't fully seat the ball. The good thing about black powder is it burns so slow - you can't hardly stuff enough in a revolver cylinder to blow it up. You also need to apply a dab of grease over each cylinder to avoid multiple cylinder discharge (plain old Crisco shortning will do). Set a percussion cap on the cone / nipple - and you're ready to go. Clean up is best accomplished with scrubbing the cylinder & barrel in soapy water - drying & oiling. Make sure to thoroughly clean the cones. Use gun solvent to clean the frame.
Black powder shooting is very labor intensive. But compared to modern large caliber centerfire cartridges - it's very cheap. And it's a lot of fun. The low kick, characteristic black powder boom and lots of smoke make for a different experience from shooting modern cartridges & guns.