Unfortunately, what you now need to purchase will take as much money as you spent for the gun. Assuming it's a caplock:
.440 round balls
2f or 3f powder, either real black or synthetic (Pyrodex P)
powder measure capable of 50 grains
powder flask or horn
0.010 .45 cal patches (to start, .015, .020 or pillow ticking later)
patch lube (or buy pre-lubed patches)
.45 cal cleaning jag
black powder solvent
And a good tooth whitener as you'll be grinning from ear to ear after shooting it.
Some optional items: ball puller, patch puller, range rod.