Im sorry to burst your bubble.But, it's near impossible to convert a sketch up model AKA: non brush model to a interior.I can convert it for you. But, it's likely to have missing faces, maybe even some texture issues.
Would you do that? Please? And could you take pictures of what it looks like in-game?(But what do you think of it? :o)EDIT: What do you use? Toque Constructor?