I can find almost nothing about her. A Russian Wikipedia article for her mother, Julia Alexandrovna Konova, has this (approximate translation) about her, "Elena (1800-1891), in 1815, was married to an employee of the Russian embassy, Count Alexander Petrovich Apraxin (1784-1845), while staying with her mother in Vienna. In 1841, at a very mature age, she married Hungarian aristocrat Count Joseph Esterházy (1791-1847)." This may be a wedding or wedding-related portrait.
Upgrade image posted 29 November 2013 also from the museum Web site.