I've had the same issues. The search is dreadful. I was going to open a ticket for the forum module when I got a chance (I think it's the same as this forum on SS). I continuously have to go to Google to search this site.
I agree that forum searches could do with being a bit better. The ability to search specific forums would be a god send, or at the very least, the ability to search for a whole phrase enclosed in inverted commas.