In above config by desiibond, you can change proccy+mobo to X3 8650+ for 4.5k and a cheaper mobo such as 740G based for around 3k... Since you are getting separate gfx card for around 5k in the config, you can go for better proccy and mobo with less powerful igp...
Also, a HDD for about 2.5k and cabinet around 1k is missing in the budget, but will fit in within 25k...
Arun