Easily. I have the same card. It will support 2 DVI monitors, or you can get a adapter which will run from dvi to 2x vga (+ 1 dvi). Or you can run one DVI and one HDMI monitor.
Lost frames will vary depending on the games and what you're running on the other monitor. If you run a movie + a game it will affect FPS if not also the heat. My card runs about 5-10C hotter with 2 monitors. Some games will disable the other screens, and have minimal FPS loss. On the other hand some games like Supreme Commander can use multiple monitors and actually runs faster because it doesn't have to dynamic scale the map quite as often (game has a lot of "zooming").
Yes you can do it, yes it's worth it, and no it won't affect your in-game FPS too much unless you're running graphics intensive programs in the other window, or using extensive video post-processing when watching HD movies.