What to upgrade in my PC?

[iPenatrate]

Hey guys. I'm looking to upgrade my pc and wanna know what parts i can keep and what parts i should get. I'm going to post my pc specs later in this writing. Anyway, i was looking to get the AMD Radeon 7850. I also wanted to upgrade to an Intel Core i5 or i3, but that would mean replacing the motherboard and such. Is it worth it? By the way what other things should i upgrade after seeing my PC specs? I'm a big gamer and wanna make this PC good. By the way i have a Galaxy GT 520.
Machine name: OWNER-PC
Operating System: Windows 7 Home Premium 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.120830-0333)
Language: English (Regional Setting: English)
System Manufacturer: Dell Inc.
System Model: Inspiron 570
BIOS: BIOS Date: 12/20/10 17:36:20 Ver: 08.00.15
Processor: AMD Athlon(tm) II X2 245 Processor (2 CPUs), ~2.9GHz
Memory: 4096MB RAM
Available OS Memory: 4094MB RAM
Page File: 3339MB used, 4848MB available
Windows Dir: C:\Windows
DirectX Version: DirectX 11
DX Setup Parameters: Not found
User DPI Setting: Using System DPI
System DPI Setting: 96 DPI (100 percent)
DWM DPI Scaling: Disabled
DxDiag Version: 6.01.7601.17514 32bit Unicode

 

[Brett928S2]

Hi

All of it ...... for gamer its just too old...

All the best Brett

 

[iPenatrate]

So replace everything?lol

 

[djangoringo]

Not even the case or psu since it's a dell one...you could probably salvage the dvd drive and hdd if the interface it's a sata one.
But you'll have to buy most of it all parts(psu,cpu,mobo,ram,etc, including the 7850)