I understand about $$ being tight with kids, college etc., however here's the flaw in your plan. With the stove you purchased, you are still going to need to burn oil.
I would beg or borrow the $$ to install the boiler which will completely eliminate the need to burn oil. Your pay back will be quick given the crazy price for oil and your savings will be greater, allowing more to go to the other expenses you mentioned. Higher initial investment but much greater return. I'm spending money I don't have now (don't ask me how) to build a bunker to store 24 tons of coal. Buying in bulk every four to five years also yields greater overall savings.