Not really, it's sounds rather impossible to fit more information into less space when it's just fixed pixels. The image is simply down-scaled by the projector, leaving out details.
Sure, there are neat algorithms to give the appearance of more detail but there's a limit to what you can do with it especially when we're talking about small-size text. Consider that displaying a lower resolution on a higher resolution projector is basically a science in itself when it's not evenly dividable and the opposite becomes rather hard to do good.
An external scaler or trying to make the graphics card rescale the output instead could possibly result in a slightly better image, depending on how it is doing this. But an external scaler of good quality might cost you what a new projector would anyway ^^
What you could do is try to increase the text-size with the DPI setting in say Windows - it will still be fuzzy though - but might make it more readable. In the end, it's a bit silly, use the native resolution of the projector and adapt the user interface instead - like making the text smaller, window borders thinner and so on...