Help me identify my bottleneck please.

Should I (a) upgrade components, (b) sell or dismantle and rebuild?

I have $250-$300 max to upgrade or sell off and rebuild.

I use this mostly for gaming Battle field series games including BF3 and family use for Syncing iPhones (qty 3) and ipads (qty 2)to a seagate 2TB external drive over 3 users ID.

BF3 is a little jumpy at ultra but about 25-30 FPS at high settings.

Thank You in advance.

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System Information
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Time of this report: 6/9/2012, 12:51:04
Mother Board: AUSUS M4N68T-M
Operating System: Windows 7 Home Premium 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.120330-1504)
BIOS: BIOS Date: 12/21/11 15:15:09 Ver: 08.00.14
Processor: AMD Athlon(tm) II X4 630 Processor (4 CPUs), ~2.8GHz
Memory: 4096MB RAM
Available OS Memory: 4096MB RAM
Page File: 2259MB used, 7975MB available
Windows Dir: C:\Windows
DirectX Version: DirectX 11
DX Setup Parameters: Not found
User DPI Setting: 96 DPI (100 percent)
System DPI Setting: 96 DPI (100 percent)
DWM DPI Scaling: Disabled
DxDiag Version: 6.01.7601.17514 64bit Unicode

Storage : ST316031 8AS SCSI 150 Gig
Starage : Seagate FA GoLex Desk USB 2TB

Optic: ATAPI iHOS104 SCSI CdRom
Optic: SAMSUNG CD-R/RW SW-252S ATA

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Display Devices
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Card name: NVIDIA GeForce GTX 460
Manufacturer: NVIDIA
Chip type: GeForce GTX 460
DAC type: Integrated RAMDAC
Device Key: Enum\PCI\VEN_10DE&DEV_0E22&SUBSYS_13623842&REV_A1
Display Memory: 2530 MB
Dedicated Memory: 738 MB
Shared Memory: 1791 MB
Current Mode: 1360 x 768 (32 bit) (60Hz)
Monitor Name: Generic PnP Monitor
Monitor Model: SK-32H640G
Monitor Id: WDE17A6
Native Mode: 1360 x 768(p) (59.799Hz)
Output Type: HDMI
Driver Name: nvd3dumx.dll,nvwgf2umx.dll,nvwgf2umx.dll,nvd3dum,nvwgf2um,nvwgf2um
Driver File Version: 8.17.0012.9573 (English)
Driver Version: 8.17.12.9573
DDI Version: 11
Driver Model: WDDM 1.1
Driver Attributes: Final Retail
Driver Date/Size: 2/9/2012 21:13:00, 17642816 bytes
WHQL Logo'd: Yes
WHQL Date Stamp:
Video Accel: ModeMPEG2_A ModeMPEG2_C ModeVC1_C ModeWMV9_C