Career
She set her personal best for the Half Marathon of 1:13:03 at the 2005 IAAF World Half Marathon Championships in Edmonton, Alberta, Canada. Her personal best in the marathon came during the Nagano Marathon in 2006, with a time of 2:29:46. Rillstone set a national record for the marathon at the 2007 IAAF World Championships in Osaka, Japan, with a time of 2:33:58, finishing in thirteenth place.
Rillstone represented New Zealand for the 2008 Summer Olympics in Beijing, and competed in the women"s marathon.
She ran and finished the race in sixteenth place, with a best possible time of 2:31:16, nearly two minutes short of her personal best set in Nagano.