Thanks guys for the very advanced help. After a long thought I decided not to upgrade.
The prices will lover in few months and spending so much money to get maybe 8 fps more seems very unreasonable.
I hope in few month I will be able to buy some better quality CPU, RAM, Motherboard and SSD and after many years I will be able to take the game into the next level.
Once again I would like to thank you for the help and very reasonable advices, and wish you wonderfull time.