Forex Excel Formulas

I’m interested in doing some back testing on data that I collected.
Instead of doing it manually I want to use excel to help me with the process.
I have a few indicators that I use in order to determine entry and exit points in my future trading system.
These indicators are: MACD, Parabolic SAR and RSI.
I tried to find excel formulas for these indicators online but I didn’t manage to find something useful.
I wonder if any of you have an idea where I could find such excel formulas.
Thanks in Advance, Drue.