Hi Sunil,
I can see that in column you have used customer also, it means there will be different opening balance for different customer in lable. So according to my knowledge its not possible in Bex, you can acheive it in webi/crystal/workbook(with macro).
If there is only one opening balance you want to display in text then go for customer exit variable, which will read opening balance in customer exit code.
Again, I guess you need to filter on only single month instead of YTD. so customer exit variable will read the closing balance of previous month.
Regards.
Ashish