Download the Nvidia GeForce 326.58 Beta driver, Windows driver version 326.58. These provide beta support for OpenGL 4.4 and GLSL 4.40 on capable hardware.
You will need any one of the following Fermi or Kepler based GPUs to get access to all the OpenGL 4.4 and GLSL 4.40 functionality. Mind you that this is a Beta development driver. We have a discussion thread open on these drivers right here.