Yahoo! Voices has this about the portrait, "These unique artistic gifts helped Goya to unveil the truth behind his paintings, opening the door to social commentary. This combination of features can be seen in the painting of 'Marquesa de Pontejas' (1786) and even more strongly in the portrait of 'Therese Louise de Sureda' (1803-1804) in which the rich colors of the chair and dress of the subject are in sharp contrast to the tense, angry face of the subject. She looks out, challenging the painter, her glare and upright posture a commentary on her true nature. Never was there a portrait of a woman at once so attractive and hostile simultaneously."
Outside of this portrait, I cannot find anything about her.
From en.gallerix.ru/album/NGA; image made lighter by gogm.