I'd actually say to skip the original movie and just jump into this one if you're curious. The first movie starts off interesting, and then just stops making sense pretty quickly.
Plus, the original was a Geneon title, so there may be non-trivial issues in getting it, unless WHV manages to score the rights for the original and re-releases it. Still, I grabbed my copy of the first movie not too long ago at a Borders, so it's plausible that other retailers will have a copy lying around.
-- Ed