I need a formula to calculate avg 2 months sales on each item.

If I were basing it last years sales, I would use:

{Sold LY}/6

But I also want to include this year sales:

{Sold YTD}/todays date minus April 1, 2012 divided by 2

Anyone know how to do this? It doesn't have to be exactly 2 months avg, just something close. Also, rounded to zero decimal places.