some of the apps in this article seem to have gone away). That also explains why the only legit Star Wars apps you can find are by Lucasfilm or a licensee such as Angry Birds, Legos, etc.
Will they take your house? We can't tell you what will happen if you post your app, but like Palpatine's army of clone warriors, the Lucasfilm legal staff is an efficient goal-seeking team. Their initial focus will be on closing down the app, not eviscerating your bank account. It is usually only after Lucasfilm lawyers have been rebuffed that they file a lawsuit. But of course, our information is all hearsay, and Lucasfilm is entitled to seek damages or an order seizing your servers. By the way, offering the app for free shouldn't make any difference as to whether your app is closed down.
Bottom line dept. Because apps like yours take a lot of time to prepare, and because yours is likely to be shut down, our advice would be to change the story line so that it's not based on the Star Wars movie series. Of course, you'd also lose the network of fanboys so we can see why you might want to disregard our advice and share your work with the Jedi world. In that case, may the force ... etc.
Related entry: Is Star Wars blog illegal?
For more on app legal issues: Protecting Your Mobile App
Invaluable New Invention: OSM