This section contains spoilers for: Dragon Age: Origins.
After awakening from a coma, the Warden can speak with Ashalle at the Dalish Camp. The Warden can persuade her into finally telling them about their parents, and will provide a key to a chest containing an Heirloom Necklace.
She is encountered again at the Post-Coronation party in the Royal Palace, if the Warden survived the battle with the archdemon. If the Warden asked for land for Dalish, she's surprised it happened and joyful to no end.
Ashalle is not with Marethari's clan during Dragon Age II because she is still in Ferelden. If the Warden is of Dalish Elf origin, Ashalle is managing the Dalish boon.