Just type Injustice Gods Among Us in the seacrh bar. The issues can be purchased for .99 cents and a new issue is released every Tuesday. I don't know if you know this, so if I'm just telling you what you already know, sorry. If you'd rather own a physical copy, check your local comic book store, they usally have the issues collected in three chapters for a single comic. They net about 3.99.
I would like if you could add real synopsises onto the comic page on this wiki, as that was what I was planning to do myself, but recent events have reminded me why I never liked joining sites like these.
Sorry for laying this down on you, I may just do it myself as a random Wiki Contributer, but I doubt it.