Here is how to refute Jehovah's Witnesses' claim that Jesus is saying in John 17:3 that He is not God.
Jehovah's Witness - My New World Translation quotes Jesus saying to God in John 17:3, "This means everlasting life, their coming to know you, the only true God, and the one whom you sent, Jesus Christ," so Jesus is saying that he isn't the "true God," is he?
Christian - No, that is not what Jesus is saying (Take him through the fifth, sixth and seventh paragraphs of this page, starting with "What is meant by 'και Jesus Christ whom you have sent'?").