Williams Llanelli Wales

I am looking for the family information of James Williams, born Llanelli Carmarthenshire abt 1813

In the 1851 Wales census he and a wife Sarah and son William were listed in

71 Talywain, Trevethin, Carmarthenshire and his occupation is a Blacksmith.

They have a daughter Margaret, baptised Swansea 1852 and the family emmigrated to South Australia aboard the ship Shackamaxon Oct 1852.

As I have no information as to either James or Sarah’s families in Wales I am hoping this story sounds familiar to someone.

Sarah’s surname could be Jones but I have no proof of this.