add on furnace

hi everbody im new to the forum
i recently purchased a home with a forced hot air furnace ( i came from a coal boiler home) and would like to add a coal stove/furnace to the forced air set up
i have done some searching but could find what im looking for. looking for something that i can hook into the duct work,has a hopper that holds enough for a few days where to start?? any suggestions or recommendations thanks in advance for your help

BINGO!

http://nepacrossroads.com/about4903.html

if you can find used that is not sold that will probably be you best bet for this year.i bought a keystoker koker and hooked to furnace last season.nothing but praises it worked as intended and better,got to warm and had to open doors and windows a few times.no experiance with others but i am very happy with my koker. i don't think my oilman is though