If the bearings are worn out, you really should take the crank and have it checked out by a machinist and see if its still in spec. If it is, you could just order new bearing the same size and put it back together. If it's not, then you will have to get it machined and go the next bearing size up, or more, depending on the condition of the crank. Some one with more experience and knowledge will come along soon and explain it better than I.
