Possibly upgrading my Alienware m15x 's Nvidia geforce GTX260m graphics card. Please help!!

Hello, I Have an Alienware m15x that I use primarily for gaming. In the last 6 months the motherboard and hard drive have both been replaced. The laptop is no longer under warranty. Recently I have been experiencing a lot of problems. After restoring the laptop back to factory condition and a fresh install of all drivers including my graphics card driver I began experiencing black screens and freezing while playing world of warcraft. I would have to shut down the computer and restart and it kept happening. A tech friend installed a different driver and that stopped but now my games WoW, sims 3 and Diablo3 are constantly freezing during play. Kinda hard to raid with a freezing screen lol. The laptop has been getting very hot for several months now and when playing my temps on my video card are jumping from 56 degrees celsius to anywhere between 87-98 degrees celsius. My tech friend is suggesting I upgrade the graphics card and apparently there are several possible options for my laptop, my problem is not knowing much about graphics cards and which would be they best option to replace my existing card with(Nvidia geforce gtx260m) without also breaking my bank account.To be honest Im not even sure the problem is the graphics card. Dell is no help anymore on information as the computer is no longer under warranty. The most I've been told is I can purchase the same card I already have from them for 380.00. If anyone can help me out with any of this I would greatly appreciate any and all advice or suggestions. Hopefully I've provided enough information as I wasn't sure how much to copy in.

System Information
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Time of this report: 3/12/2013, 14:56:51
Machine name: PHURY-PC
Operating System: Windows 7 Home Premium 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.130104-1431)
Language: English (Regional Setting: English)
System Manufacturer: Alienware
System Model: M15x
BIOS: Ver A08 1.00
Processor: Intel(R) Core(TM) i7 CPU Q 720 @ 1.60GHz (8 CPUs), ~1.6GHz
Memory: 4096MB RAM
Available OS Memory: 4084MB RAM
Page File: 2236MB used, 5931MB 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

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DxDiag Notes
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Display Tab 1: No problems found.
Sound Tab 1: No problems found.
Sound Tab 2: No problems found.
Input Tab: No problems found.

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DirectX Debug Levels
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Direct3D: 0/4 (retail)
DirectDraw: 0/4 (retail)
DirectInput: 0/5 (retail)
DirectMusic: 0/5 (retail)
DirectPlay: 0/9 (retail)
DirectSound: 0/5 (retail)
DirectShow: 0/6 (retail)

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Display Devices
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Card name: NVIDIA GeForce GTX 260M
Manufacturer: NVIDIA
Chip type: GeForce GTX 260M
DAC type: Integrated RAMDAC
Device Key: EnumPCIVEN_10DE&DEV_0618&SUBSYS_02A21028&REV_A2
Display Memory: 2791 MB
Dedicated Memory: 1005 MB
Shared Memory: 1786 MB
Current Mode: 1600 x 900 (32 bit) (60Hz)
Monitor Name: Generic PnP Monitor
Monitor Model: unknown
Monitor Id: LGD020C
Native Mode: 1600 x 900(p) (59.978Hz)
Output Type: Internal
Driver Name: nvd3dumx.dll,nvwgf2umx.dll,nvwgf2umx.dll,nvd3dum,nvwgf2um,nvwgf2um
Driver File Version: 9.18.0013.1407 (English)
Driver Version: 9.18.13.1407
DDI Version: 10
Driver Model: WDDM 1.1
Driver Attributes: Final Retail