Philpot

Hi
I'm trying to find information about my Dad's side of the family.I know that his grandfather was John Joseph Murphy and his grandmother was Elizabeth Murphy whose maiden name was Philpot I can't seem to go back any further than this.I am a complete beginner on family tree.I have paid subscription to a couple of sites but find myself stuck.I would love to go back further into my family tree.So any information about either of the above named people would be a great help to me.
Thanks
Michael Murphy