Upgrading Laptop

[adrenalined]

Hello everybody , i am so glad i find and join this great site.I am looking for some help with my Acer 7520G which for about 3 months now has been giving me problems and recently has quit completely to work.
A quick journal of failure 7520g:
1)playing COD and similar games i noticed lots of lags,changed drivers but the problems remained and gradually got worst.I OC the 8600m gs and finally i had to remove the nvidia drivers because the screen in win7 was locking up.It worked with the standard vga drivers just as a laptop for internet access,youtube etc.
2)Cooked the Gpu worked for a month then back to standard vga
3)acer logo boots ,before win7 boots the cpu restars again and again...
4)the laptop opens the hdd is heard but there is the endless cycle of rebooting and switching off by it self
5)Hot aired the nvidia chipset on the mobo yestarday,didnt work

So i am having a plan in my mind, keep caddy and slowly keep upgrading the whole system.
A)Motherboard -Has anyone buy one from ebay? warnings,advices welcomed!
B)whats the best GPU mxm type II (money aside).Is the ati 4670 still considered the best gaming card i can put inside?will it work with the 7520g?What could i do to make it perform
C)CPU i want to try the TL-68 .does the 1.33 bios work with this?Is there a modded one?
D)Can i exceed the 4GB limits of ram?
With rough calculations i estimate about 450-500 euros for new M/B,CPU,GPU.
How good you think this will work on the new games such as COD-mw3...

I know too many questions.have already have gone through many threads, i am looking for a more condensed theadon experimenting/upgrading 7520G!

Thank you all!
Links :
TL-68:MOBILE CPU AMD TURION64 X2 TL68 TMDTL68HAX5DM 2.4GHZ Amilo XA2528 XA2529 | eBay
ATI HD 4670 :ATI Mobility Radeon HD 4670m GPU MXM 2.1A | eBay

 

[AntiZig]

If I may ask, do you want to do this just for the heck of doing it as a personal project?
because for the same money you planing to spend on 2 generations old GPU you could get a brand new laptop with better cpu + gpu

 

[adrenalined]

No i am actually trying to save money using the existing parts i have (cpu+memory+caddy&screen)For the new mobo+Gpu i estimate around 280euros.But even if i change evrything all at once then i reach around 500->600 top.Which laptop would you recoommend?Would you recommend a motherboard that can carry modern Gpu's?