Hi,
(I''ve moved the topic here where it fits better.)
I don''t know of any suitable Plato resources off the top of my head, I''m afraid, but I would strongly suggest that you don''t go down the road of seeking out other people''s past essays. Firstly, you cannot acknowledge other people''s essays as sources (and if you don''t, then it''s plagiarism); and secondly, you run the risk of repeating their mistakes (if there are any).
I know it''s not easy, but your essay will be much better if you manage to track down some primary resources. I would start with Karl Popper''s "The Open Society and its Enemies" (or commentaries on that), which is one of the most sustained criticisms of Plato''s political views (start of with Wikipedia, and go from there). Also, a good book on political philosophy should act as a good starting point - what books are you currently using?
By the way, the quotes are the result of a problem with the forum which I''m still trying to fix...