How to get Open potentials with date filter through API

How to get Open potentials with date filter through API

Hi,
I can able to get values using "https://crm.zoho.com/crm/private/json/Leads/getRecords?authtoken=%s&scope=crmapi" which gives all values but i need to get count for only specific period (i. e I need the open potentials count for the period between 17-03-2014 and 23-03-2014). Let me know how can get the same. But in Zoho UI , i can see it under Reports with custom filters, i need the same through API call.
Thanks in advance.