1)
Who is "Yoshev ha'Iy ha'Zeh"?
1.
Rashi: Bnei Eretz Yisrael, who relied on Pharaoh for help. "Ha'Iy" is like "Iyei ha'Yam" (11:11).
2.
Radak: Eretz Yisrael is called Iy, for it is on the sea shore.
3.
Malbim: Eretz Yehudah, who relied on Egypt and Kush. They could not help themselves - how can they help others?!
2)
What is the meaning of "Asher Nasnu Sham l'Ezrah"?
1.
Radak citing Targum Yonasan: They intended to flee to [Egypt] to be protected from Melech Ashur. [Egypt] could not save themselves - how can they save us?