Your RT device should already come equipped with a media player, although if you want VLC media player you can get that here.
To stream it from your computer, have you tried sharing the folder with your media files on your desktop and then accessing it from your surface?
Technically if you wanted to, you could create a shared folder on your surface using this, and then copy the files you want watch directly onto the surface device itself.
If you stream videos to your devices often, I highly recommend you install Plex Media Server. You install the Server on your desktop with all your videos, and then you install the client onto your Surface tablet. Think of it as a sort of personal netflix, only it gets its content from your computer, which you provide yourself.
With my android MX Player worked well BUT it was on Windows App Store, but when I got a card to some purchases it cannot be found. If anyone knows if it their let me know too, but bottom line is a really really good app as far as android and if done
Same for windows surface/windows period I think you would joy it to me was really nice since I have converted most of my dvd's and blu-rays into avi's.