If what she held in her left hand was a lotus then we are looking at Green Tara. If it was a manuscript it could be Sarasvati (although she is usually playing a string instrument) but she would normally hold a grain in the other hand held at heart level. Her very bulky jewellery includes two different ear ornaments and she wears her thick long hair gathered on one side. It is thought that the sculpture may be contemporary to or a later copy of the following.
It is not known whether this sculpture was made by Choying Dorje (the tenth karmapa) himself or by someone from his atelier, or someone imitating his style (unlikely but not impossible).
This is a very similar image, with slanted eyes and no navel, which shows that several versions of the same sculpture were produced at the same time and in the same place, the object in her hand vaguely resembles a manuscript.
Attributed to Choying Dorje but without certainty. It could also be the original of which the previous two are a copy.
This goddess, on show at the above-named exhibition published on http://www.asianart.com, is clearly related to the previous ones and has been the object of highly diverging opinions as to where (Bhutan or Tibet) and when (7th-9th or 17th century) it was made. She has a similar hairstyle, with the bunch gathered on the other side, holds what seems to be a manuscript in the left hand and wears two different bulky ear ornaments. She also wears a short skirt-like garment, a plain necklace and matching bracelets.