Instead of ready made tomato puree you can use tomatoes and puree it.
Can use peanuts alone instead of using all the three nuts.
Roast the chopped capsicum only till the skin is slightly browned and should be added to gravy at the end before switching off the stove.
I have used ginger garlic paste for grinding you can use whole garlic and ginger for grinding.
Can use other colors like red and yellow capsicums or in combinations will be great.