That library does not seem to be maintained any more, whereas Apache POI -and its HWPF component- have been updated quite a bit over the last 7 years. While it's possible that WordAPI.exe can do what you're asking, I'd say that it's also worthwhile giving POI another look - which can definitely do that.
In that case I would change your template so that it uses the font you want. Or perhaps check the documentation to see if setting the font is an option in that software? I don't have access to the site where you got the software from so I can't read it on your behalf.
As for that website which you linked to: it says that Apache POI is not very useful for producing Word documents. This was true in 2004 when the blog entry was written. It's now seven years later and things have changed. You could consider using POI if that software you have there turns out to be a dead end.