If you have a serious home theater, then you need a better projector which can deliver the better blacks. This starts with the JVC RS46 which is about $2,600ish.
At $800 you are entry level, and the black levels, while decent, don't match the JVC models.
Also, as pointed out, you don't have a serious home theater. You have a normal room you can turn the lights out in and doesn't have windows. That's very different than a home theater space. Since front projection relies on a quality room for best results, you just can't get it with what you are providing at this time. Get some dark paint for the walls and ceiling and put in some dark carpet and things will improve immensely.