|The term CARD is frequently mis-used - any device adapter that's built into the mboard IS NOT A CARD and cannot be removed.|
In most cases the video adapter for a laptop or netbook is built into the mboard and cannot be removed.
If it's a higher end laptop that costs a lot more than average for the same or similar cpu and main chipset, it may have a removable video card module, but usually you can only use the same video card as it had in it originally, unless another model in the same series has a video card that's better that you can install, and it's usually only available by buying it from the brand name system's web site, unless there are used parts available for your model series on the web.
By the way, the amount of ram an onboard video adapter can use, or the amount of ram on a video card, after a minimal amount of ram has been exceeded, has nothing to do with how well the video adapter performs, except that the more ram that is available to it, the better the max frames per second rate is at the highest resolutions.
If you can't use the highest resolutions because that makes the detail of what you see on the screen too tiny, or because your built in display or external monitor doesn't support that, there's no point in having a video adapter that can use / has more ram for the video - the max frame per second rate for the same video chipset is identical for the lower resolutions whatever amount of ram the video adapter can use / has.
For a laptop, you would probably not benefit from the difference between having 1gb rather than 512mb available for the same video chipset unless you connect a much larger display externally.