Can I petition my child?

Im a green card holder married to a US citizen. I have a son in the Phils. and he is not under my name, he is under my sister and her husband's name. When I was interviewed by the Immigration for my visa, I declared that I have a son but they didnt know he wasnt under my name. So how can I petion him how can I bring him here in the US, beside seeing a lawyer, I s theres somebody have a case like I have? is anybody know? can you tell me what to do? Im miss him so much. so please help me what to do.