Calculate events during a certain period

Hi experts,

Need some help...
I´m trying to make a calculation based on static events during a certain period (weeks), but when you move forward to the following week I want to keep the same information on that cell, to have something like a time evolution.

Maybe an example will more clear,

Events type	nº events		date week	Event A	Event B
A	5		1	5	10
B	10		2

So if in week 2, event A = 10 and event B = 8, I would like to maintain the previous values in the week 1,
and so on, ...

does this makes any sense?
Thank you for your support