1)
Why does it say to take a harp?
1.
Radak: This is a metaphor - Tzor should do like a forgotten Zonah - she takes a harp and goes around in the city, after she was hidden in her house and sees that no one comes to her. Perhaps a man will see and hear her, and her voice will be pleasant to him, and he will come to her.
2)
What song should Tzor increase?
1.
Rashi: Increase supplications and lower your pride.
