League Table with previous week ranking

Hello

I've a league table excel and i'm trying to make creator a columm with the previous week ranking. After thar i' ll compare with the current league position and create arrows tom see if the team has gone up ou down in the table.

But i'm having troubles, i don't now if its better to create a temp sheet wit the values or insert a formula that gives me the information.
Any help would be appriciated.

I'm attaching the file.

Thanks in advance