Not much help but Ive had a root around and it seems that Danny Elfman wrote the whole score for the film, which I presume will include the opera music. Cant tell you much more than that
It's "Lacrimosa" by Immediate Music, an outfit who create music for trailers/ads. I think you can get their stuff on CD, but couldn't be bothered to trawl through their site - I'll leave that to you: http://www.immediatemusic.com/html/body_news.cfm