I haven't played BF2 however I have been playing a whole lot of BF2142 and it is supposed to be just a slightly modified version of the BF2 graphics engine.
I have pretty much the same set up as you do with the dual 256 cards and I have BF2142 set to max in all catagories except I keep antialiasing off as that causes problems if it is on. But I mean everything is maxed even the resolution as I have a nice external monitor I play it on that can actually handle 75mhz refresh rate.
In your case I only ask what video drivers are you using right now. If you are using the oem shipped ones that Alienware installed then you may want to go take a look at www.laptopvideo2go.com
I'm using the 93.71's as they are very stable so far. I'm thinking of moving up to a 96.xx version here really soon just to see what happens. If you don't know how to install these it is actually quite simple. Click on the driver version you want and download the zipped file to your documents folder or wherever else you tend to download files to. Unzip it. Then immediately to the right of the driver version on the website there should be an INF file. This is a modified inf file that makes the driver able to work in a mobile pc. Download that file then drag and drop it in the unzipped driver folder. Choose yes to overwrite the INF file.
Go into your device manager and then uninstall your video adapter drivers. Upon restart of your computer it should recognize a new hardware. When that screen comes up go through the process of finding the new driver through the "have file on disk and use browse" than just click on the driver version file when it comes up. You will have to do this for both of the video adapters. Once said and done you can then restart your pc and check out all the new options nvidia has available for you in their redesigned options screen. They should also have a profile in your SLI properties for BF2 that is optimized for SLI machines.
If you have any questions just ask.