The magazine Nintendo Power will be having a preview and poster for the release of the new TMNT game next month.
Check out
Toys R' Us's turtle section. They have information on a lot of TMNT toys and other merchindise (including Halloween costumes
).
Also, the new mini toy release dates have seemingly been pushed back to sometime in October. So you'll just have to wait it out.
[Thanks to ThirdMarioBro and Deciet for the heads up.]