She also received thirteen All-American honours, and earned a bronze medal in the 200-yard freestyle (1:46.97) at the 2000 NCAA Women's Swimming and Diving Championships in Indianapolis, Indiana.

[4][5] In the 4×100 m medley relay, Muller, along with Marianne Kriel, Penny Heyns, and Mandy Loots, finished fourth with a time of 4:08.16, almost a full second off the podium.

[16][17] On the last day of the program, Muller teamed up again with Loots, Sarah Poewe, and Charlene Wittstock in the 4×100 m medley relay.

Swimming a freestyle leg, Muller anchored the race with a split of 54.77, a new national record, but the South Africans settled only for fifth place in a final time of 4:05.15.

[18][19] At the 2002 Commonwealth Games in Manchester, England, Muller captured two silver medals each in the 100 m freestyle (55.60), and in the 4×100 m medley relay (4:05.06), along with Loots, Poewe, and Wittstock.