These modal verbs express slightly different things: Could = Is a polite request in this case. (in other situations can refer to a physical ability. Could you run 20km?) Would = Can be a polite request but also can mean "Potentially if I asked you for help, what would be your answer?"

There is not much difference. Both of these are polite requests. I would say that "could you" is used more than "would you" but both are correct in polite situations.

I think right question:Could you help me.