@_Maria_ , for Russian students/researchers the tax treatment of grants, allowances or other similar payments is covered under article 18 of the US-Russia Tax treaty. These are exempt from US taxation as long as the Russian citizen is in the USA "temporarily present" in the USA for "..research...". It further states that " such exemption ... shall apply for such period .....as ordinarily necessary...... except that ... no exemption for training or research shall extend a period exceeding five years". Thus if you have been here for more than five years then the exemption is not valid. Another issue is that this treaty and on this subject is only applicable for a citizen/ resident whom is in the USA temporarily --- thus your change of status to Green Card would negate this exemption.
Therefore my conclusion is that , absent any other facts & circumstances, your fellowship grant is to be treated as if you are US citizen/resident without benefit of US-Russia Tax treaty. Thus this grant will be treated as income to the extent that the funds are not used for training or education. Your living expenses are definitely to be treated as income and therefore taxed by the Feds and the State -- both will consider this income as US sourced / in-state sourced.
This is not what you wanted to hear but ....
Is there more I can do for you
pk
