Thanks. This year, ideally:
NYC-SAO: departing on 20 Dec 2013
SAO-NYC: departing on 5 Jan 2013

I know they are the busiest days, but, last year that travel agency had them for $800, which I was impressed. I though it was a price error or something like that, but no... I really got it. Kayak had it for $1500+.
Even Matrix software had them same price as Kayak.

As I said, now I don't know where to look. I've been contacting that same travel agency this year, but so far their fare is almost the same as Kayak, like $1600+.