Renaming file with increment number?

Hello.
I'm trying to figure out how to rename a file that is called "weekly plan 12" on a weekly basis with an increment number. 12 reflects the number of school weeks during a school year.
I'd like Hazel to copy the actual file into an archive folder (which I already figured out) and rename the file with weekly plan "number" + 1... how would I do that?
Thank you for any help!
I figured out how this would work... or better: it is working but it is using the wrong number. No matter the settings it counts up. I'd like to start at 11 and it counts to 20 every time I try the rule with a file named "weekly plan".
I'm trying to figure out how to rename a file that is called "weekly plan 12" on a weekly basis with an increment number. 12 reflects the number of school weeks during a school year.
I'd like Hazel to copy the actual file into an archive folder (which I already figured out) and rename the file with weekly plan "number" + 1... how would I do that?
Thank you for any help!
I figured out how this would work... or better: it is working but it is using the wrong number. No matter the settings it counts up. I'd like to start at 11 and it counts to 20 every time I try the rule with a file named "weekly plan".