On the official GAMDIAS website, there is a "where to buy" section on the top, click it and you will see where you can purchase their peripherals from your chosen country. It's pretty organised and it directs you straight to that particular retailer as well.
At the moment though, NCIX.com is where I can see these products. I still couldn't find any on Newegg.
I went to their booth in one of the conventions awhile ago, the keyboard HERMES seems pretty decent, and I really like the fact that it is in matte finish not glossy (keyboards with glossy finish is just not right, finger prints and smudges all day -.-) Another cool add-on is the wrist rest which also act as a dust cover. While I was at it, I also got my hands on most of their mice, from high end to low end (HADES, APOLLO and DEMETER). They all felt pretty comfortable and are built in nice rubbery material (Only Zeus has 3 different options on the materials I think, with one called E-sports Edition).
Headset wise, I can't wait~~~~~~ to get the Hephaestus, the cooling system on a headset and vibration to give you 4D gaming experience, it's just way too cool not to have it, but I think it is not going to be released until the other two headsets come out (Hebe and Eros). These two are more conventional comparing to Hephaestus, but I did have a try on Hebe just to see the sound quality. I have to say for its price, Hebe's sound quality blown me away. If you guys see them in retail stores around you, go try them out! Having said that though, I am still gonna go for Hephaestus for sure, lol!
P.S. GAMDIAS are going to have brown and red switches on Hermes in the near future, I think this would definitely help gamers who like to have a quieter experience.