Calculating EVA

Hey guys its probably a noob question but I hope someone can help me!

I need to Calculate the EVA with thomsen reuters datastream. I want to use the Capital Charger Formel: EVA = NOPAT - (NOAt-1 * WACC)

Is this Correct:

NOA=(Total Assets - Cash) - (Total Liabilities - Total Debt)

NOPAT=EBIT - Income Tax

WACC= ((Total Assets - Total Liabilities) / ((Toatal Assets - Total Liabilities) + Total Debt)) * Cost of Equity + (Total Debt / (Total Assets -Total Liabilities) +Total Debt) * Cost of Debt * (1- Tax Rate)

Cost of Equity= Risk free Rate of Return + Beta *( Market rate of return - Risk free rate of Return)

Cost of Debt= Total Interest / Total Debt

I hope someone can help me, its the first time that I have to use Real data, Thanks a lot!