How To Get Previous Weekly Total In Power BI Matrix Table

[CConsultants1]

Hello Guys,

I'm stuck with a problem where I need to show the last week total for all of the upcoming weeks.

in The image you can see the last available data for the week is week 12 which I want to show for all of the upcoming weeks untill new data has been added. I have used lastdate function to get the last order date then used dateadd to get the value of 7 days ago but it isnt showing the correct result. Also I can't show the last week value for all of the upcoming blank weeks. 
Can you please help me with this problem.

[amitchandak]

@CConsultants1 , refer if week rank approach can help

Power BI — Week on Week and WTD
https://medium.com/@amitchandak.1978/power-bi-wtd-questions-time-intelligence-4-5-98c30fab69d3
https://community.powerbi.com/t5/Community-Blog/Week-Is-Not-So-Weak-WTD-Last-WTD-and-This-Week-vs-La...
https://www.youtube.com/watch?v=pnAesWxYgJ8
Time Intelligence, Part of learn Power BI https://youtu.be/cN8AO3_vmlY?t=27510

[CConsultants1]

I'll surely try to use that method. But here the problem is I have to show the last week value as a forecast for all of the upcoming weeks. Can you please help me on that.