Hi Jaga,
Badi should be crm_badi_rf_q1o_read. I don't think it will have implementation for your search business object. If not create one with appropriate filter.
This badi will be called from class CL_CRM_Q1O_SEARCH=============CP and method GET_RESULT_VALUES line number 86. you can get the filter name from here.
Cheers,
Elam Bharathy