Surely you mean 2560x1440? Otherwise, that's a very weirdly proportioned monitor.
Upscaling will usually look terrible (at least, it does for me), so stretching 1920x1080 to fit 2560x1440 will most likely look bad.
However, you can use the Nvidia control panel (from what I've read) or possibly the monitor (which is what I do) to perform no scaling on images. This means that if you set your game resolution to 1920x1080, it will display a 1920x1080 image at the centre of the screen. I've use this a few times now and it seems to me that the quality is the same as if you were just using a smaller monitor (one that's right for the resolution you chose).
Though, if you're getting this monitor solely for gaming at 1920x1080, don't bother - it will either look ugly or it will look the same as your current monitor (depending on if you stretch it or don't scale it).
I run IL-2: CoD at mostly high settings and 1920x1080 resolution with a 560 and an i5 2500k, so it's possible that you could run it at 2560x1440, but I guess it's very dependent on what kind of FPS you're aiming for. 2560x1440 has roughly 1.7778 times as many pixel being displayed as 1920x1080, so that certainly isn't a small increase...I don't know, really, hopefully someone else can help you with the graphics card side of things.
Also, I would imagine that at 2560x1440 you would still have aliasing to worry about. Why not try downsampling with what you've got right now? That is, set the game to run at 2560x1440 on your 1920x1080 monitor (you'll have to look up how to get downsampling to work, though, because this doesn't work by default). It won't show you exactly how much AA you'll get from a larger resolution (it might look like less aliasing/more AA than if you were using the appropriate size of monitor), but if it still looks very aliased you'll know that a monitor upgrade won't help much.
Here's one link of many for downsampling:
http://forums.guru3d.com/showthread.php?t=346325