Do I upgrade my CPU or GPU for CS:GO

[debrajsaikiaclashofclans]

I am thinking of doing something with my old shitty PC so that I can play CSGO with good FPS.

*My budget is around Rs.5000 (75$)* So my question is what should I add or replace?

Specs-
Processor: AMD A4-3300 @2.5GHz with integrated Radeon HD 6410D
Motherboard= Gigabyte - GA-A55M-DS2 Micro ATX FM1
RAM= 1xCorsair - Vengeance 4GB (1 x 4GB) DDR3 + 1x 4GB RAM DDR3
PSU= 450W
Storage= 500GB Hard disk

I have no idea whether I should buy a GPU or replace my APU, please help me out.
I have no intensions to upgrade it later as I would be buying a good gaming laptop after 1.5 years

 

[vapour]

750 ti is your choice

 

[Calvin7]

A8‑3870K is available for that price. An updated BIOS version may be needed before installing it.

 

[debrajsaikiaclashofclans]

Will getting a good GPU for around 80-90$ help me get 120 fps?

 

[RememberThe5th]

GPU has no impact on csgo perfomance at all, the cpu is limiting you.
From where can you buy, and where are you located/living (country only).

 

[debrajsaikiaclashofclans]

Amazon India