I'm sure you know this already, but the album is available digitally (I don't believe it ever saw a physical release) through iTunes, not even the Japanese one. I haven't found a leak of it anywhere, but it's only $5, not asking for much.
I'd grab it for you, but after listening to samples I'm really not a fan of this soundtrack. I loved NieR's soundtracks, even some of the weird remixed tracks, but this is just an underwhelming album. I'm not going to try to convince you it isn't worth it, but I'll tell you that some of these Western takes on Japanese game music don't hit it off too well, so it may be hard to find a copy if you aren't looking to pay for it. Anyhow you can find it here:
https://itunes.apple.com/us/album/nier-gestalt-replicant-jazz/id685614171
And a 2nd Volume was released in the last couple months as well:
https://itunes.apple.com/us/album/nier-gestalt-replicant-jazz/id883838477