the answer with clear steps please

In order to provide for R12 million to build a new warehouse in six years' time, a company plans to make equal payments at the end of each three months into a fund which earns 8% per year interest compounded quarterly. After three years of payments, escalating costs lead the directors to increase the quarterly deposit so that the fund will contain R15 million at the scheduled time of the building. Find the increased quarterly payment required for the remaining 3 years