I hate weekly reporting.
Yup, we can't build a straightforward date based on week values.
But consider this. Find your starting date for the first week of your corporate calendar. For instance, this calc:
I just plugged in a hard-coded date of January first. Datetrunc gives me the first day of the week that the supplied date falls in. The result is 12/31/2017. Assuming that's what you consider the beginning of the first week of your year, then you can do this:
DATEADD('week',[your week value], [calculation 1])