You need to go with a new module.

One way to do this is inherit from hr.payslip, and patch the method get_inputs so that you go over employees attendance, check if worked on holidays and his attendance records and create inputs for them.

class hr_payslip(osv.osv):
    '''
    Pay Slip
    '''
    _inherit = 'hr.payslip'

    def get_inputs(self, cr, uid, contract_ids, date_from, date_to, context=None):
        res = super(hr_payslip, self).get_inputs(cr, uid, contract_ids, date_from, date_to, context=context)
        contract_obj = self.pool.get('hr.contract')

        for contract in contract_obj.browse(cr, uid, contract_ids, context=context):

            """
               Your code here to find out if emplooyee has more than 75% attendance.
               Suppose you set a flag called 'good_attendance'
            """
            input = {
                 'name': 'Attendance over 75 percent',
                 'code': 'ATTENDANCE_OVER_75',
                 'contract_id': contract.id,
                 'amount': good_attendance,
            }
            res += [input]

        return res

Then you create a rule that checks for ATTENDANCE_OVER_75 input and adds a bonus if true...

Similar will be for checking if employee worked on holidays...