1 8800GT vs. Crossfire New Monitor

[DethWish12]

Ok I need some advice please. This is my current system:

Power Supply - http://www.newegg.com/Product/Product.aspx?Item=N82E16817371007
MSI K9A2 Platinum - http://www.newegg.com/Product/Product.aspx?Item=N82E16813130136
AMD Phenom 9850 - http://www.newegg.com/Product/Product.aspx?Item=N82E16819103249
4GB Corsair Dominator RAM (2x2GB) - http://www.newegg.com/Product/Product.aspx?Item=N82E16820145197
1x GeForce 8800GT - http://www.newegg.com/Product/Product.aspx?Item=N82E16814127329

Running XP Pro and using a NEC 19" LCD at 1280x1024.

I am looking at upgrading my monitor, this is the one that I am looking at - Acer 24" Widescreen - http://www.newegg.com/Product/Product.aspx?Item=N82E16824009125

My question is: Is my current system good enough to run current games at the new monitor's resolution (1920x1200)? Or do I need to upgrade my graphics card. I was looking into it and found that my board only supports crossfire, not sli, so I was looking at getting 2x ATI Radeon HD 4850's - http://www.newegg.com/Product/Product.aspx?Item=N82E16814121253

$182.99 x2 = $365.98

Is it worth the price or should I just stick with my current card? I am mostly going to be playing Warhammer Online.

Also, on a different topic, is it worth it to upgrade to Vista 64 bit in order to use all of my RAM? It currently says that I have 3.25GB. But I heard there is a lot of headaches and nothing is compatible with 64 bit yet.

Thank you very much in advance.

 

[dagger]

Dual 4850 will certainly be far faster than a single 8800gt. Although if Warhammer Online is the only thing you're playing, 8800gt will still be able to handle it.

If you have retail Windows Vista, call Microsoft and they'll mail you a 64bit version disk for $10. Then it's worth it. You have to use the same key for installing the new disk. If you use OEM Vista that comes with a pre-built computer, they won't do it.