application for leave to remain as a bristish child's paren

Hi ya, please i need your advise.
I came into the uk in 2010 with a student visa, my post study work visa expires in 3 weeks time.
I am a parent of a british child and I want to apply for leave to remain via flr fp route.

Questions: must i go through a solicitor for my application?
do i need any document from my ex boyfriend and what documents do i need to submit.
your responses are very much appreciated