Performance Tuning :: Temp Tablespace Running Out Of Space (68 GB)?

I am getting temp tablespace error "ORA-01652: unable to extend temp segment by 128 in tablespace TEMP" for the following code.

SELECT /*+ USE_NL ( vd1 ,vd2 ,vd3 ) leading ( vd1 ,vd2 ,vd3 , tvd) */ vd1.vendor_record_seq_no,
tvr.checksum, tvr.rownumber, tvr.transaction_type, 'U'
FROM vendor_data vd1, vendor_data vd2, vendor_data vd3,
(SELECT rownumber, MAX (DECODE (control_column_seq_no, 91150, original_value, NULL)) AS value1,

[code]...

Right now used tables has the following number of records-

SELECT COUNT(*) FROM vendor_data --292890442
SELECT COUNT(*) FROM temp_vendor_data --0
SELECT COUNT(*) FROM temp_vendor_record --0

This query is part of an application, but consuming too much of temporary tablespace (68 GB allocated). I found it out by using query below:

select * from v$session a, v$sql b
where a.sql_id=b.sql_id
and status = 'ACTIVE'

I am not sure, why this problem is occuring.