Cronenberg's one of my favourite directors, so kudos on your obvious good taste, mate
Most of the ones you are after will more than likely be available on Amazon (or marketplace) - most should be pretty cheap, too.
Cosmopolis hasn't been released on DVD yet (October I think?), and just a heads up that the Universal release of
Videodrome you have, will not be the full uncut version.
I think the Criterion version is the only fully uncut release available on DVD, but will be fairly pricey and Region 1/A locked (it's definitely worth the extra money though, imo). The short film 'Camera' is also available as an extra on the Criterion
Videodrome release.