Complex sentence: Kristinn was dismissed from RÚV (his contract was not renewed) in July 2010 and has since worked as an independent journalist, collaborating with WikiLeaks and stepping up as the organisation's spokesman as founder Julian Assange withdrew from the limelight.
Split into simpler sentences: Kristinn was dismissed from RÚV (his contract was not renewed) in July 2010. He has since worked as an independent journalist, collaborating with WikiLeaks and serving as the organisation's spokesman after founder Julian Assange withdrew from the limelight.