I would buy the 1954 Singer if it's in good running condition. They are workhorses and can be maintained by you. I would keep Grannies old machine and look into refurbishing it. A motor is likely to cost alot (maybe $100)and you would also have to fix the wireing, not cheap if you don't do it yourself. You might just do what I did with a simular old machine, put a handcrank on it (cost a little over $20).