I don't think watching the news or reading it would help with improving your written expression tbh, the language used in news etc is always quite detached, objective, and more suited to reports than the style of writing expected of your teacher.
If you're looking to improve essay writing read anthologies like
Australia's Best Essays [insert year] (they come out annually), or critical analysis of well known texts (online literary journals for eg). The Times magazine isn't bad either. But to improve vocabulary and written expression in general i think reading texts valued as literature is always helpful. Another thing is the introductions of Penguin Classics for books such as
Frankenstein and most literary works, these are actually quite good too, their use of language is always clear, concise, and sophisticated.
Just a few suggestions, good luck anyway.