A quote that begins with a quote

For an English assignment, I have to find passages in my book that correspond to a certain literary element. For one of the passages, I have a dialogue that I would like to use, but I'm not sure how to correctly quote it.

Ex.
"'You're a hopless loser, son,' Trueba would say, sighing. 'You have no sense of reality. You've never taken stock o fhow the world really is. You put your faith in utopian values that don't even exist.'
'Helping one's neighbor is a value that exists.'
'No. Charity, like Socialism, is an invention of the weak to exploit the strong and bring them to their knees,'" (337).

The beginning with the three quotation mark is one double quote and the beginning of a single quote, is this correct grammar? Should I also remove the space, or keep it? This is meant to be in MLA format.

Thanks.