help selecting graphics card

[#1]

Hi.
I'm buying a new monitor a ViewSonic VP 2770 which has a screen resolution of 2560 x 1440.
My graphics card a ATI Radeon HD 2400 Pro spec is    Max Resolution Details DVI: 1920 x 1200 / VGA: 2048 x 1536, so I am looking for a new graphics card. I've looked on Google, Amazon and eBay but they don't quote screen resolutions. I would be grateful if anybody could suggest a suitable graphics card.
It's not for games, the system is used for spreadsheets and share charting programs.
I it would have to support 2 monitors the new ViewSonic, my existing monitors which has a screen resolution of 1680 x 1050.
My motherboard is a Asus P5Q

[#2]

Most of the modern ones would give you what you want
For Nvidia just find the one you are thinking about here http://www.geforce.co.uk/hardware/desktop-gpus
For ATI this is the start point http://www.amd.com/UK/PRODUCTS/DESKTOP/GRAPHICS/Pages/desktop-graphics.aspx

[#3]

your motherbord has a PCIe2 slot so most any latest GFX card will fit , the main concern is your PSU , or power pack a new GFX cards require a extra power connection .
So before you make a choice Check your PSU has or hasent got a PCIe power connector , or a spare molex to connect a PCI adapter to it .
as for any preference of AMD or Nvidea ? AMD cards a lower price for performance Nvida  give a little  better performance
i would suggest somthing like this
http://www.overclockers.co.uk/showproduct.php?prodid=GX-345-SP&groupid=701&catid=56&subcat=1984
this card is able to display ultra high resolutions of up to 2560 x 1600 at 60Hz.

[#4]

I think it will be expensive as you will be sold a games graphics card.
You ought be able to find a passively cooled device.

[#5]

I've tried to look around for something with a good cost against what you wish to use it for.  To run any monitor over 1920 x 1200, you'll need a dual link DVI connection, which the radeon above has, but i found this exact model, passively cooled:
http://www.scan.co.uk/products/1gb-sapphire-amd-r7-250-ultimate-800mhz-1125mhz-ddr5-128-bit-dvi-i-hd...
It's also got a HDMI output, which you can get a HDMI to DVI cable to run your second monitor too!

[#6]

If you're not gaming or similar then this may well suffice: http://www.businessdirect.bt.com/products/sapphire-technology-ati-radeon-hd-5450-650mhz-1gb-ddr3-pci...

[#7]

Thanks everyone, really helpful posts.
I'm now looking at replacing my (six-year-old ) PC but that's another story.