As far as I know there are 3 ways the new attachments are obtained: dropped off Pup-type mobs, solo ENM 60, and ISNM. The Pup mobs drop the tier II (The ones with II actually in the name, Tension Spring II, Loudspeaker II, etc etc) while the specialty attachments from ENM/ISNM. Which drop from which, I don't yet know and only one of any of them has been listed on the AH so far (Eraser, no sale price as of yet).
I tried the solo ENM and although it started off very well with me getting a nice chunk off Fantoccini's HP, thanks to that bastard of a goblin friend he has he got healed, his maton got buffed, all that fun stuff which lead to me being face down on the floor. Fantoccini was cake, his maton was rape-in-a-can© though. Think I figured out a fool-proof strategy (Well, nearly, a lot will depend on the goblin's rolls) that I'ma try once my timer is cooled down. I'm curious to see if there's a ring or something you can get too.
None of the new attachments sound like they're particularly spectacular, although I haven't been able to get my hands on most of them yet to personally try them. I wouldn't bother spending too much gil on them, I was lucky enough to get all the tier IIs off of Trolls; only ones that I use regularly are Tension Spring II and Loudspeaker II which are definitely nice. In time they'll be more common and most likely drop in price, or you can just ENM/ISNM for them yourself. Once I get some of them I'll definitely test them out and post some info.