Kolchak started out in a very successful TV movie called The Night Stalker, which was followed by a sequel called The Night Strangler. They were then planning to do a second sequel called The Night Killers, but then the network decided they wanted a series instead. They probably would have used Night Killers as the two-hour premiere of season two if the show wasn't cancelled.
Did you watch the movies or series when they were on the air?
Looks like the only option currently is DVD. It's pretty cheap and worth it. It got on the air because of the success of Raiders of the Lost Ark, but it really has more in common with stuff like Terry and the Pirates; and it has a great cast, including Roddy McDowall.