lemonjuice,
Does this happen with the basic fonts (Arial, Times New Roman, Courier)? If so, you may need to change one of the settings in your printer driver.
While I don't have access to a dot-matrix printer, I seem to recall there's a setting that tells the driver to download fonts as images, as opposed to fonts.
Locate this, set it, and then see what happens. It will slow printing significantly, but if it works, well, that's all there is to it.
There are some good deals on basic laser printers these days. (I think you can get an entry level model for ~$150.) It might be worth the investment.
Hope this helps...
-- Lance