Hi I am researching my family tree and have come to a dead end

My G Great Grandfather William Sellars born abt 1834, married Harriet Slack in Sheffield, 30 May 1860, after purchasing the Marriage cert, I have found that his father was called George Sellars, and was still alive at the time of the marriage - Im not sure who Williams mother is, and haven't found a definite birth date for William either, all I know is most of my family, originated from Masbro or Kimberworth in Rotherham, It appears that William was born in Rotherham, maybe Scholes - any help with this part of my tree would be greatly appreciated, as im not sure which other certs would prove who the parents are, the only definite I has was the marriage of William and Harriet, hense finding the fathers name is George

Thank you in advance for any information ;) x