Praise be to Allaah.
Firstly,
There is nothing wrong with you giving gifts that are beneficial and free of anything that is forbidden according to sharee’ah to this non-mahram woman through someone else without meeting or talking to that women.
Secondly,
If there is fear of tending heart or fitnah then it is not right for a girl or woman to give hadiya to any non-Mahram boy or man.
But if there is no fear of fitnah due to faithfulness or by any other reason i.e. the person whom the hadiya is being given is too pious and religious person or he is quiet ignorant with the woman or the gift is given through any male mahram then it is allowed as per the Shariah.
And Allaah is the Source of strength.