Save your money and put it towards a bike that makes more sense for your riding. A BD Moto-becane (which is just a bought name with no sense of quality or history attached) with a freewheel is not a bike to put money towards, run it into the ground and if the frame is ok donate to a charity that takes bikes and save your money for the bike that has the shifting and braking you want and ideally find it at your local shop.