13 weeks rolling with customer

In general, if you cannot share your pbix, creating a sample report reproducing your issue will give more precise answers: How to Get Your Question Answered Quickly

Since you have not shared anything, I will assume your model only contains a single table, 'Orders'. I would at a separate date table, with relationship to order.

Then I would create this column in the date table:

WeekYearNum = 
var _startDate=DATE(2016,1,1)
var _currentDate=CALCULATE(SELECTEDVALUE(Dates[Date]))
var _distinctWeekNumbers = CALCULATETABLE(VALUES(Dates[Year-Week]),Dates[Date]<=_currentDate)
return
COUNTROWS(_distinctWeekNumbers)

This is a running week-year-number, so you can easily move back/forward any number of weeks, without having to think about changing years. 

With this column you can write your measure like this:

Sales last 13 weeks =
VAR _currentWeek =
    CALCULATE ( SELECTEDVALUE ( Dates[WeekYearNum] ) )
RETURN
    CALCULATE (
        SUM ( 'Table'[SalesCol] ),
        FILTER (
            ALL ( Dates ),
            Dates[WeekYearNum] > _currentWeek - 13
                && Dates[WeekYearNum] <= _currentWeek
        )
    )

Then drag the Dates[Date] into the filter for your visual, choose relative date filtering, and choose show last 13 weeks: