How do I figure out "Cost of Debt" Problems? - after-tax cost of debt calculator, bond

Here lies the problem: Please give me a simple way to solve this problem, and if anyone knows how to use a Calculator Texas Business instrumets you tell me how.

Zephyr Corporation is considering a new investment will be funded at 33% debt. The company was able to sell new bonds at par value to $ 1000 net price of 945 $. The discount is 12%, and bonds maturing in 15 years. If the company is located in a level of 34% VAT, which is what the after-tax cost of capital bond markets to Zephyr?

Do Show me how to be and how and what # 's are: N, I, PV, FV, and payment

Please Finance Majors