I always make my own curry paste by putting the following ingredients into the processor:
Onion, garlic, ginger, fresh chillies, sweet chilli sauce, lime pickle, mango chutney, a squeeze of lemon or lime, coriander seeds, cumin seeds, fenugreek seeds, hot chilli powder, black peppercorns, garam masala, tiny pinch of cinnamon, and cardamon pods. (It helps if you crush the spices first). You could try marinating the meat overnight, which would tenderise it, and adding yoghurt during the cooking process.