I guess you didn't check amazon.com, as there are many many dvd and vhs copies available, both new and used, very inexpensive. I have a DVD version. In the same vein, check out Days of Wine and Roses, the original Playhouse 90 version with Cliff Robertson and Piper Laurie. Available only on VHS and a bit more expensive at $20+ but definitely worth it for the quality of the acting and production.
Now, this other film, or actually, series, that has alcoholism as one of its central subjects, is Brideshead Revisited. Waugh's view of alcoholism is pretty much pre-AA, and so should be taken with the appropriate grains of salt.
But, he does get curiously close to it, and there is a back life which gives a richness to the portrayal of a young alcoholic, Sebastian, who goes quite to pieces in a fairly short time. It's the portrait of his character that is better than most. One reason, I think, is because it's not trying to make a point, but rather just tell a story, so the character is not engineered to make the point, so you can get closer to him, feel more of what is going on with him. I felt sort of breathless at times. And there was also the great Catholic forgiveness, and, well, fatalism, which alcoholics may fault, but at that time AA was in its American infancy, and most alcoholics just simply died of it, with not much hope.
By the way, do watch the 1982 version with Jeremy Irons and Anthony Andrews, not the remake.
I've seen a few other things of Jeremy Irons, but I feel this role really defined him.
Hard to believe, but they came close to casting him as Sebastian, and Anthony Andrews as Charles.
Brideshead Revisited is one of the finest adaptations from a novel ever made. But, they were going to do it in six hours, started making it, encountered, I think, a technicians strike, and during the lull, decided to up it to twelve hours, which did extravagant justice to the book.
John Mortimer, who did the screenplay, has never done anything mediocre that I know of.