3D Graphics cards are generally designed for things like games. Large numbers of low poly count models with textures. When you're doing 3d-modeling, you're working comparatively few, high-polygon models. Hence the bit about the graphics card not helping very much. CPU/Ram is what you're going to want the most of. It's funny that you describe those specs as horrid, because when I was getting into 3d stuff, that was absolute top of the line. I remember my college roommate getting a computer about like that and we were all so jealous of him.