Rick Stein's "India" television series and associated cook book may be the way to go. I cook a lot of curries, but found that the recipes that Rick discovers in the T.V. series really helped me to get out of a rut.
Two recipes from the series/book that I can think of are:
The book: Rick Steins' India - on Amazon
If you can find the T.V. series, or the Youtube clips, it really helps to inspire.
IIRC whilst Mutton refers to a sheep of around 2 years or older, in the india recipes, I believe that Mutton actually means goat.
I really recommend it - three months of travel and food discovery packed into 6 episodes. It'll inspire you and you can pick up all sorts of knowledge and advice, whilst being entertained.
Remember, if you don't have a particular ingredient, you can often substitute for something similar - if you don't have dried kashmiri chillies - use another mild/hot chilli pepper. If you don't have red onions, white/brown onions are fine.
I prefer basmati rice, it's so different to American Long Grain rice, but, if you're in a pinch - then long grain will suffice. No lamb? Try goat, beef, etc.
In the series, Rick uses mustard oil for some recipes, but I substitute sunflower oil, or ghee, or coconut oil, depending upon the recipe. I might throw some mustard seeds in for good measure.
No curry leaves? Perhaps try a bay leaf.
Some ingredients are more essential though, you can't really substitute Cumin seed/powder, Turmeric, or coriander seed/powder.
Most of my spices in my cupboard are whole seeds that I either use whole, or grind if powder is required. This seems to give a better flavour and longer shelf-life.
Edit: The recipe for the Rogan Josh is about 20 minutes into ~~episode 1~~ - no - it's actually Episode 6, I think that the episode naming/numbering is incorrect.
I sort of winged it, but it was inspired by a curry in Rick Stein's India. Meen Masala, or Bombay Salmon Masala Curry.
I really recommend the the book that accompanies the series