Digital Projection

I have a BenQ MX520 digital projector and it's use was fine in my previous house, however since I have moved to a new house, the rooms are smaller and the 'throw' of the image onto the screen is relatively small, even on the widest zoom position. I don't know if there is a 'standard' where lens fitting/focusing is concerned so alternatives may not be available. Ideally a different lens with a wider angle would be better but I would like to hear from anyone who also had this problem, and how they solved it. The booklet that came with the projector states there is no alternative lenses available.
(The image size for projection is 1024 x768 pixels, quite adequate for my needs. It is about 3 years old.)