Unfortunately your graphics card does not support the latest in
Hardware T&L. This will likely cause problems in many modern games.
On
this page I found a list of compatible games. Although NWN2 isn't on there, I can assure you it needs that Hardware T&L. You can however use that list to see what other games you could try out.
I know it is kind it is harsh, but you are definitely not the first to make a mistake like that. Asking for a refund on the game shouldn't be a big deal.