Seasons 3 and 4 Up For Preorder On Amazon For Sept. 26, 2013!
Looks like VEI <Visual Entertainment Incorporated> will be releasing seasons 3 and 4 as half season sets just like seasons 1 and 2 all at the same time on September 26, 2013. Amazon has a listing, and here is the link :
http://www.amazon.com/exec/obidos/ASIN/B00EJRTYOI?tag=viglink123527-20
They should be popping up on the other websites that sell dvds soon so not sure who'll have the best price yet. Now we just have to wait for season 5!