This is definitely an interesting question, because with the arrival of her father Kira has all the proof she needs that the Guardians whom she serves have probably killed her mother and definitely desposed of her father to try and control her talent and gain her, just as they have done the same for Jo and Thomas. However, above all, Kira feels her magical ability to weave desiring to express itself in the Singer's cloak, and even though she knows how the Guardians are manipulating and controlling everyone, she feels she needs to remain true to her talent and calling. Note what the text tells us in the final chapter:
Kira could feel it in her fingertips: her ability to twist and weave the colours into the scenes of amazing beauty that she had made all alone, before they assigned her the task of the robe.
It is Kira's ability, then, that makes her want to live, and in an excellent move, the author returns to this magical, breathing talent as the novel ends, leaving Kira in a very uncertain position:
The blue was gathered in her hand, and she could feel it quiver, as if it had been given breath and was beginning to live.
Her talent demands the ability to express itself, and this is above all why Kira chooses to say and face both her knowledge and her talent.
She decided to remain in the village rather than going with her father because she felt that she had to do something about how the council was treating her community. Since she heard about how the community where her father had lived all those years, how they were kind to each other, she felt that she should help her village instead of abandon it because that would be the same as abandoning the friends who need her.