If you missed getting your hands on Playmates Toys awesome 6" scale Retro Classic Teenage Mutant Ninja Turtles, Turtle figures the first time around then you will get a second chance in August. The latest issue of Previews magazine has them along with the new Rocksteady and Bebop figures solicited for release in August 2013. Coming from Previews means these will be available at your local comic, specialty or etailer store.
The figures will also be showing up at mass retail chains like Toys R' Us at some point, but if you don't want to have to hunt around for them then you may just check with your local comic or specialty shop and see if they can order you a set through Diamond. The item code for these is MAY131878.