brakes work as a system. for decent braking you need good calipers, good cables and housing, good pads, and a good levers.

I suspect the bike is not worth too too much, but if it has a certain value to you, and you do not mind investing some money into it, get some tektro 73mm reach dual pivot brakes, stock pads are fine, some good stainless cables and lined housing, and some inexpensive tektro cantilever levers. These are relatively stiff, have decent pads, and insane amounts of tire clearance and reach. Furthermore, they are a snap to set up.

Drum brakes need purpose built hubs.

I can't imagine that you have the ability to corner... this thing must have a really low BB.