Materlized View refresh (complete )is now very slow

Here is the syntax of MV.

CREATE MATERIALIZED VIEW PPADMIN.RPT_HERTZ_SUMM_ACTIVITY_VIEW
TABLESPACE MAT_VIEW
PCTUSED    0
PCTFREE    10
INITRANS   2
MAXTRANS   255
STORAGE    (
            INITIAL          64K
            MINEXTENTS       1
            MAXEXTENTS       UNLIMITED
            PCTINCREASE      0
            BUFFER_POOL      DEFAULT
           )
NOCACHE
NOLOGGING
NOCOMPRESS
NOPARALLEL
BUILD DEFERRED
REFRESH COMPLETE ON DEMAND
WITH PRIMARY KEY
AS
/* Formatted on 12/4/2013 8:44:46 PM (QP5 v5.252.13127.32867) */
SELECT TOTALS.CLIENT_ID,
       TOTALS.RAC,
       TOTALS.TOLL_REGION,
       TOTALS.WEEK_START_DATE,
       TOTALS.YEAR_NUMBER,
       TOTALS.WEEK_NUMBER,
       TOTALS.AGREEMENT_COUNT,
       TOTALS.TOLL_COUNT,
       TOTALS.TOLL_DOLLAR_BILLED,
       TOTALS.FEE_DOLLAR_BILLED,
       TOTALS.TOTAL_RENTER_INVOICE,
       TOTALS.FEE_DOLLAR_BILLED - TOTALS.ATS_NET_FEES AGENCY_GROSS_FEES