Great
This song was very, very nice! You captured the essence of sadness very well in this piece. This is something you might expect to hear in a movie where someone dies and it flashes back to important moments in that person's life, if you understood that at all. Fav'd.
And I did find the strings to be decent. Unfortunately I don't got any idea of any free one's. Just try fiddling around with the EQ and the string you like most until you get a sound you like.
I suggest adding just a bit more reverb to the piano.