Video cards are output only, and I am not aware of any cards for computers that are hdmi/dvi input (I haven't looked lately), but In the great unix tradition headless operation presents several options to do what you want to do quite simply.
Unfortunately making the RPI truly headless is a bit difficult (it doesn't have a easy way to use a serial console), but psudo headless is almost as good and we only have to hook up a monitor when something goes wrong.
All of my examples use ethernet, so get your network working first.
Now as to the level of pretty you want there are three classes of pretty command prompt, window, and desktop.
command prompt is easy install a ssh server on your RPI (sudo apt-get openssh-server) and putty on your windows box.
window is a little more involved, first get ssh setup as above, Install a X server on your windows box. (I use Xming) then setup X forwarding over ssh. The cool thing about this approach is that you can have windows from the RPI mixed with windows from windows.
There are two ways to export a full graphical session from the RPI to windows XDMCP and VNC. XDMCP is not secure, and a little complicated but may give better performance over high-speed networks because more of the graphic processing is offloaded to the windows box. VNC is much simpler see my answers to Black screen with X cursor when running VNC on boot or How to configure xorg.conf for widescreen VNC on headless Linux/Ubuntu? for details on my favorite way to do this.
