International Capital Asset Pricing Model (CAPM)
When using DCF you would discount using the weighted average cost of capital; and yes you can then find the expected return on equity using CAPM - if you have beta. But how do you know what beta is in your case?

That being said it seems like you are just using DCF for the 6 years where you know the cash flow? Will the company seize to exist after that? If not, you need to discount all future cash flows as well making assumptions on how income/profit will continue in the future (usually a constant growth rate from e.g. Year 10-15 and into all eternity).