Hi Anghellix,
I'm from India, and I'm currently in the first year of the PhD program at Ohio State. Although my experiences of applying to grad school here are atypical (I applied to just the one school), I know that the application and admissions process can seem particularly difficult to navigate from so far away, so feel free to message me if you have any specific questions and I'll try my best to answer them.
I didn't take the GRE Lit, so I can't answer your questions on that front. I do want to second what ExponentialDecay says about working on other aspects of your application--from what I've been told, your writing sample and SoP are by far the most important parts of your application. (Good GRE scores are important, but they will be read in light of other parts of your application.) Competition for PhD programs here is keen, and admissions committees will primarily use your writing sample to judge how prepared you are for a research degree. In my experience, Indian colleges don't emphasize writing and argumentation in the same way as colleges here, so you'll want to devote as much time as possible to working on your sample. I would also recommend familiarizing yourself with how American universities demarcate literary/cultural periods, as applications are often evaluated by faculty in the period you apply to research in (yet another thing that's different from the Indian system). It might also be worthwhile to look up the most recent issues of an influential journal in your period in order to get a sense of what debates and issues are current in the American academy. Often, these debates are very different from those in the Indian academy, and are not reflected in the syllabi back home.
Good luck!