Amazon.com, Things From Another World, Forbidden Planet, iTunes.
And while you wait to get hold of a copy, you can also check out some more artwork from Cat Staggs, who illustrated this issue. Posting on her blog she released some concept art for the new aliens featured in the story, and also shared a bunch of her inked pages (pre-colouring), like the one below. You can see and read more on her blog.
To keep track of all the latest Star Trek comic releases, hit the comics button on my 2015 schedule page.