Financial Modeling for a solar systen distribution, service and micro-finance company

We are a one year old pico solar sales, marketing and distribution company. We have an existing financial model that became over time unmanageable and I want to create a new model with current performance numbers (we have a Chart of Accounts and QB accounting) and future projections. I need the model to be able to input variable investment tranches over time with options to enter variable dates when an investment (debt or equity) will come in, when the payback start date is, the finance period, interest etc. I need this done very fast.