Personally, I LOVE a good esoteric movie reference and am 100% guilty of it myself. In addition to constant
Office Space references, I like to toss in a few zingers from
Real Genius. But the key is to know your audience.
While Star Wars has been around for over 30 years and everyone knows the title, not everyone is going to have seen the movies or get it. I really think that a gentle conversation with your sister about *why* it's annoying, including that a lot of strangers might now get the jokes.
And I'm not kidding when I say this could be done intervention-style. It sounds that bad. You had me cringing with the cop part. Gahhh...
I guarantee she will grow out of this or at least make less frequent references. So, at your conversation/intervention (still not kidding!) I would make the following steam vent suggestions:
1. That she make Facebook memes. There are already a million of them, but she might have fun with it!
2. Silk screen some shirts with these memes.
3. Start a Facebook group or join an online forum for fans.
Or...find a more current franchise she can become obsessed with. Since Dr. Who has a pretty large current fan base, at least any references would have more of a chance to be understood.
When she makes comments, walk away, change the subject, anything to...feed not maker of quotes.

I hope this works out for you!