Sirs,
As mentioned above by one of colleagues there are a lot of enterprises available in the market you can purchase for your organization to do the work on your behalf just customize the leave rule and it will work.
On the other hand since you have requested an excel format to be used please find attached excel document for calculating leave for your organization.
However, please do go back to your human resources manual and apply your rules on the entitlement, and the overtime and carry forward.
Regards