Gord,
Getting new speakers depends on if you want to get replacements that are Sunn speakers or not. If you want Sunns, browse the "classifieds" section of the forum and eBay, or post that you're looking for some in that section. If you don't mind putting non-sunn speakers in, you could go to any music shop and get a pair of speakers, as long as they're the right size and power rating you're fine.
Unfortunately, there's no manual up on this site, but one of the forum members may have one that they can scan and email you.
~R