Crikey! That's one huge video file!
My first thought (which isn't too helpful) is to order some professional web hosting and host it online. For a video of that size you'll be looking at a dedicated server (£70 GBP + per month).
My second (slightly more helpful thought) is to upload it to a site such as the pirate bay. Yes, it is an illegal torrenting site, but your video won't be breaching copyright so you should be fine. The point being - there's tons of huge videos on there, so they'll be used to coping with the size.
Thirdly and finally, don't take this the wrong way but, why do you need it to be that big? That's an INSANE detail level - DVDs fit onto a 4.7GB disc, and you don't see many people complaining about the quality of them, now do you? This point is, simply, compress it a bit more. If you reduce the quality so that it is roughly 1GB in size, and offer your viewers a Blu-ray DVD shipped to their door with the full quality film on, that should cover everything!
Okay, that might be going a bit far...but you get the point! =)