Skull vector (?)

Below are my "struggles" - first is a "normal" bitmap picture, second is a vectorised bitmap. You can see a harsh hue cutoff, because if I would increase scans, my computer would explode.
Due to my lack of patience with curves, I worked this problem around: I made a raster picture and then converted it into vectors. Who could forbid me?
BTW: do you know anything affordable other than Inkscape?