I think listening to some tapes and watching some movies/news in French would help my comprehension, but it's primarily my speaking skills that concern me. And for that, there's no substitute for regular conversation.
First of all, I think you'd be shocked to see an actual transcript of conversation in French (or any other language). It's very different "stuff" from the sort of language most people seem to want to learn.
As far as expanding your repertoire of conversational language, movies can be great (as can soap operas) -- it all depends on what you do with them. If all you do is "watch" them, then you're right that this will only work on your listening comprehension. On the other hand, if you listen AND WRITE DOWN "chunks" of conversational language you will soon find yourself recycling some of those chunks in your own language use.
The main difference between novice and expert speakers of a language is that experts have access to a much larger repertoire of "stock phrases," while the novice tries (often in vain) to generate utterances based on a grammatical scaffolding. In contrast, experts are primarily cutting and pasting from prior experience.
I regularly have my "false beginner" language students watch movies and record "chunks" in a journal. What is amazing is how different the chunks they write down are from anything they would generate themselves.
BTW, here are a couple of my favorite quotes (which I will leave unattributed because I suspect that this would please the writers):
'It has been noted before that to a very considerable extent everyday language is built up out of combinations of such prefabricated parts. Language is, in other words, to be viewed as a kind of pastiche, pasted together in an improvised way out of ready-made elements.”
“And I repeat my own prior words, not just those of others. I reshape what I hear and read, make it my own, and use it over and over again, reshaping as I go. My competence is in reshaping. I accumulate a repertoire of prior texts which are evoked when I read or hear an Other, and out of that changing accumulation I speak and write and understand. None of us can plumb the depths of our plagiarism.”