im not sure you can buy a computer from adk that's going to be anything less than a grand.
are you handy at building your own ?
you can build a nice computer for around 600 bucks that will run sonar x2 really nice.
a 6 core amd phenom 2 / 8 gigs of ram / a mobo,ram,cpu combo is like under 200 bucks.
Intel will set you back in price, I use both but find little difference besides occasional loading times.
a cheap video card like an entry level NVidia with dual DVI monitors
so you can run 2 monitors will cost about 60 bucks.
a silent case 100.00
shock mount silent fans,25 bucks.
and the hd another 100.00 (a Solid State Drives (SSD)
watch a few of these vids and see if its something you think you can do.
http://www.youtube.com/watch?v=g0TVqlgQeto http://www.youtube.com/watch?v=br-hkfdPYy4 http://www.youtube.com/watch?v=H8LlaZTSXRc I've built many of these daw's that run great running sonar, both x1 and x2.
as well as Cubase, ableton live and other daw's.