You should really try hard to convince them to let you build. Even if money isn't an issue, you'll get much better results building on your own.
That said, there's really nothing wrong with that computer. It should be using an Athlon 64 FX-53 (any $2000 machine should unless it's a server or something), and it's a little overpriced, but you won't do any better with OEM companies. If you can find a site where you put in request and they custom design and build it for you, that might be (I know of such sitses, but don't know any specific ones) better. In any case, that's a powerful machine and you won't have problems playing any games at rediculously high settings.