If you want to stick with nVidia (saves you from scrubbing their drivers) a Zotac 210
has two DVI ports. There are other models with differnt ports, you need to be careful to buy the right one. You can use a HDMI-DVI adapter for resolutions up to 1920x1200.
On the AMD side there's a 5450 from Sapphire with two DVI ports, but it's not even listed on their web site. The same warning about very similar card with different ports applies.
These are the most basic cards, the latest 7750 card might get 1-2W lower in idle, but they cost around three times as much and need a dual slot cooler for passive cooling.