Hi Moeyy,
Ok in your case we will have to look at the second hand market, Carbonite is a great place for this if you look at their rated sellers.
For CPU look at Ivy Bridge i5-3570 & i7-3770 CPU's, you have a H61 MB which does not overclock so no need to go for K-series CPUs but if a K series comes up at a good price that's also fine. I honestly have no idea what these older second hand kit goes for.
For RAM try and get 2x 4GB DDR3 1600 sticks.
Your PSU is 450W & a Thermaltake which is not the best quality and I have no idea how old it is but they do degrade with time. Considering this I would suggest a Galax GTX960 4GB from Wootware or if you could find another make on Carbonite second hand it's also ok. They overclock really well, don't use much power and run cool (depending on the make/model).
Wrt those games you mentioned they will all with the exception of witcher 3 run above 60FPs.
GTA 5 I run at about 80fps, CSGO around 200fps+, Witcher 3 at about 50fps. That said games like GTA 5 & Witcher 3 are not maxed out but pretty close where I would drop things like shadows, grass, visibility range etc a notch. I find the optimal setting by looking at the Geforce Guides from nVidia and play around with the settings until I'm happy and it's really hard to notice the difference unless you stand still and start closely looking at pixels.
http://www.geforce.com/whats-new/guides/grand-theft-auto-v-pc-graphics-and-performance-guide
http://www.geforce.com/whats-new/gu...-hunt-graphics-performance-and-tweaking-guide
Witcher I've noticed you don't have to play at 60fps plus. I found the sweet spot above 45fps, below that it feels laggy to me.
On Carbonite PM PotterH and see if he can help out with one of those ivy bridge cpus & ram, you never know as he might have something. He sells a lot of stuff and has a good rep.
I have R6.5k to spend (the price of a ps4/xbone)
This is what I currently have:
CPU - Intel g2020 LGA1155
RAM - 4GB 1333mhz DDR3
Motherboard - AsRock H61M-VS3 (mAtx)
GPU - None
PSU - Thermaltake litepower 450W
Case - Xigmatek Helios mAtx
HDD - 500GB 7200RPM
I will be buying a full HD 1920x1080 monitor in the near future.
I would like to keep the motherboard and psu if possible.
I do not wish to overclock.
Games that i want to play are - GTA V, CS:GO, Guild Wars, Spintires, Team Fortress and Witcher at 60FPS preferably.