GTA 4 on Build 7057 64bit

I need a bit of a hand here. When playing GTA 4, the game's option menu lists 230-ish megs seems to think I only have 256megs of video to work with and not the 512 in SLi. You can see by my system specs that my PC should be giggling at the tiny amount of information GTA4 will ask it to process, but yet it stutters, lag and hangs everytime I press the accellerator. It also hangs and lags when loading random people walking around.

During the installation I recieved 2 errors about bad CRC (I assume disk 2 was damaged) for both these files:

\Rockstar Games\Grand Theft Auto IV\pc\models\cdimages\componentpeds.img
&
\Rockstar Games\Grand Theft Auto IV\pc\data\maps\manhat\manhat02.img

As a note, the only non-standard part of my installation of build 7057 64bit, is the replacement of "dxdiagn.dll" copied from Vista into the \Windows\syswow64\ folder. I'm not sure what to do about this Bad CRC message or how I should install / run the game to resolve it. So in short I'm asking if someone could compress these two files, host them and message me a link.

I just want some assurance that GTA4 will work on build 7057 64bit before I go (re-)purchase a copy, that I cannot return or use, as I have no other OS to install on. :/

Perhaps someone could just test it for me? Give me a little peace of mind?

(moved to seperate thread as I highjacked the last one unintentionally.)

GTA is a very graphic intensive game and it uses allot of memory, my GTX260 has almost a Gig and the game still wants more, have applied the latest game patch to give you the extra game settings and bug fixes?

The problem is that it isn't reporting my second video card. So it refuses to let me increase the resolution past 1024x768 and crappy graphic settings. Is there a way to manually configure an .ini?

Yes their is a problem with windows using SLI in some of the builds but I think it may be fixed in the latest builds although I cant test that because I'm not running SLI.

8600s aren't enough to run GTA4 decently.