You should check out the FAQ: http://forum.toribash.com/showthread.php?t=251490
It lists a handy website that can be used to get a good solid base for a build: http://www.logicalincrements.com/
IMO $1500 is quite a lot for a build, especially just to play CS:GO. My own build is $500 and I play CS with about 180fps minimum (on a 160Hz monitor). I made this build for fun too, so it's not at all optimized. With a $700 build you could comfortably get 300fps I would say.