parents authorized stay expired, can I apply greencard for them?

My parents\' authorized stay has been expired for 3 months already. I will have my citizenship in 2 months. Can I apply greencard for my parents once I get citizenship appoved?

How can I do that? some of my friends told me it does not matter, just send the application. However, what I read from the instruction of the I-130 and I485 is that it is illegible to send the application if you are not legally stay in US.

Thank you!