Tooltip

Jyo27 , that you can not do with this week's and last week's measure, your will need two date tables one joined with your table and one not joined

Week Rank = RANKX(all('Date'),'Date'[Week Start date],,ASC,Dense)
OR
Week Rank RANKX(all('Date'),'Date'[Year Week],,ASC,Dense) //YYYYWW format\

//Date1 is independent Date table, Date is joined with Table
new measure =
var _max = maxx(allselected(Date1),Date1[week Rank])
var _min = _max -1
return
calculate( sum(Table[Value]), filter('Date', 'Date'[week Rank] >=_min && 'Date'[week Rank] <=_max))

Need of an Independent Date Table:https://www.youtube.com/watch?v=44fGGmg9fHI