I wish I could help more to you. X ------> I wish I could help you more. I wish I could help more. I wish I could be more help.

Your first and second sentences are ok and natural. The third isn't. You could say, "I wish I could help you more." Another way involves the word "of": "I wish I could be of more help to you." "to be of help (to someone)" is fairly common, and is perfectly natural.