Complex sentence: Greg (who earlier moved to another country after hearing of Rosie's pregnancy) visits Rosie at work, who had received her letter and drawing by daughter Katie, and after some arguing, Rosie decides that Greg can see Katie.
Split into simpler sentences: Greg (who earlier moved to another country after hearing of Rosie's pregnancy) visits Rosie at work having received her letter and a drawing by Katie. After some arguing, Rosie decides that Greg can see Katie.