Hi,
Let me come straight to the point. I have recently worked on a spreadsheet implementation of a forecasting model.I have tried both ARIMA and holt winters forecasting and got better accuracy with both.
I am proficient with respect to Excel and VBA as well. After going through your attachment, I am confident enough and can finish your work in just 48 hours as required. Let me know if you want to discuss further.
Regards, Sahil