I have 2 Facebook pages, both over 10.000 likes and both are active pages. Usually I get around 10% - 20% reach, but it really depends on how often you post and what you post. For example, if you make a post with an article that will take them out from Facebook, will have less reach, than a simple picture with a few words added to it. Or, if you post once a day, you will have less and less reach, while if you do it at least 3 - 4 times you might have chances to increase reach. Facebook has a big play in this, they tend to hide your post from users that liked your page, this way you will start promoting your FB page before it dies. Of course, this is not for all pages, some may actually grow very well, even without advertising.
So, in order to get 1000 clicks for one post I think you should have at least 50000 likes or more, but this will still not guarantee you exact 1000 click, it could be more or less. My best suggestion is to play around with the Facebook page a couple of weeks and see what works the best.