Yeah, especially the longer serials I find a challenge to watch. I remember the Invasion and the Silurian's I began to get fed up with. I prefer shorter ones with four or less episodes. Colin Bakers stuff is quite short.
As for the movie, yeah that's a tough one. First of all, are you American or British? If you're American, it's going to be hell to find. In Britain, the DVD's been out a long time, but in the US it's only just come out. If not on Netflix either, I'd try you tube.
It's well worth the watch, a firm favourite of mine.