I begun reading around the background only a couple of months ahead of you. So bearing in mind that a little knowledge etc..
I have found the following three books outstandingly useful.
T A Heathcote Mutiny and Insurgency in India 1857-8 Pen and Sword 2007.
This is a history covering an awful lot in 230 pages. the author has made India his lifetimes work and it shows on every page. One to begin with and then go back again and again.
Andrew Ward Our Bones are Scattered: The Cawnpore massacres and the Indian Mutiny. John Murray 1996
What can I say, gripping, moving, faster paced than a novel but academically rigorous. A terrible tale done justice to. This will plunge you into the heart of the drama.
And you must have an eyewitness memoir, of the dozen I have read I liked best;
William Wright (ed) Through the Indian Mutiny: memoirs James Fairweather. Spellmount 2011.
this has the advantage of really useful editorial notes and a further reading list.
All of these are easily and cheaply available on Amazon today you could get the lot for around £24, or through library loan.
If you read these three you would have a good idea wher you wanted to go next.