EPM Agent SQL parameters

We have this source query which is working well (see below), but we need to add a bit to update the period value.

For example, if the EPM period (~Period~) is 02 then @Period needs to become 5; 03 becomes 6 and so on and so forth.

Assuming we don't have access to a SQL Server Developer to assist in this case, is there some SQL we can apply here to update the @Period variable on the fly?

USE [SPDW]

BEGIN

DECLARE @return_value int

EXEC @return_value = [dbo].[sp_GRP_TrialBalanceUploadORA]
@Site =~Entity~,
@FY =~Year~,
@Period =~Period~

SELECT 'Return Value' = @return_value