Stir the water, milk, and quinoa together in a saucepan; bring to a gentle boil. Reduce heat to low and simmer 5 minutes, or until the quinoa begins to soften. Stir in the banana, rolled oats, oat bran, salt, and cinnamon. Cook, stirring frequently over low heat for 2 to 5 minutes or until the mixture thickens. Remove from the heat and stir in the walnuts, brown sugar, and vanilla.
