Complex sentence: Her daughter, Jane, decided to approach journalist Martin Sixsmith at a New Years Party a few weeks later, explaining the story and asking if he would be interested in helping them find out the details of what happened to the child.
Split into simpler sentences: Her daughter, Jane, decided to approach journalist Martin Sixsmith at a New Year's Eve Party a few weeks later. She explained Philomena's story and asked Sixsmith whether he would be interested in helping them find out what had happened to the child.