In order to increase computer security frameworks inside organisational networks, this research offers a structured framework for strategic investment methods.  In order to combat emerging cyber threats, proactive and cost-effective solutions are required, since traditional reactive defences are inadequate. The suggested system combines risk-return modelling and mathematical optimisation to direct the effective distribution of scarce resources across many defence layers. Organisations may achieve balanced spending, improved resilience, and quantifiable risk reduction by tying financial planning to cybersecurity goals. The results demonstrate how proactive, AI-driven investments outperform other options in reducing the likelihood of breaches while optimising ROI and maintaining business continuity.