Outdated cards don't run all the DX instructions from newer DX version thát well. They are usually optimised for a specific set of DX instructions and no amount of patching is going to fix that (had the same issue with my 7900GTO which is orders of magnitude more powerful than yours). Simply put, that architecture/supported instruction set is outdated. Your best bet would be a new computer to be honest. Also, I wouldn't adhere to the minimum specs of anything as they are the "piss-poor-gaming-experience" minimum most of the time. All in all, i'd recommend a newer computer over anything else if you want to experience this game somewhat comfortably.