Your video card does not support VDPAU but it does support XvMC, which is a precursor to VDPAU. XvMC is notoriously difficult to get working, it is not as powerful as VDPAU, and it only supports acceleration of MPEG2 videos. However, it is the only option for accelerated video playback for your GPU and Linux.
The MPEG2 format is a an older format for compressing video files. It is not as efficient as more recent formats, such as MPEG4. Therefore, software that encodes video for distribution through the internet, as well as many handheld video cameras and cell phones, will typically create MPEG4 files. However, MPEG2 is widely used for broadcasting television, both over-the-air and digital cable, as well as DVDs. Therefore, if you video is coming from TV or DVDs, then it is possible to play it back using XvMC.
The way to enable XvMC depends on your Linux distribution and requires the nvidia proprietary video drivers. Resources for installing these drivers and enabling XvMC for popular distributions can be found on various wiki:
Once you have the nvidia driver and enable XvMC, you can use it with mplayer with
mplayer -vo xvmc <video file>