A very complex query running long

Here is the Query and also attaching explain plan.

The database is standard edition and running on 10.2.0.4.

optimizer_mode                       string      ALL_ROWS

optimizer_features_enable            string      10.2.0.4

optimizer_index_caching              integer     0

INSERT /*+ APPEND */

      INTO  IFACS_SUMMARY_WORK (FVO,

                                CLIENTID,

                                SUBSIDIARY,

                                PLATESOURCE,

                                IA,

                                IANAME,

                                IARESST,

                                IARESCNTRY,

                                IAST,

                                IACNTRY,

                                IAWEBSITE,

                                IATYPE,

                                IATYPEATRESP,

                                IADEF,

                                VIOID,

                                VIONUM,

                                PENALTY,

                                SUSPEND,

                                VIOAMT,

                                CALCAMT,

                                VIOCURR,

                                APT,

                                CALCDAYS,

                                VIODT,

                                VIOTIME,

                                VIOPLATE,

                                VIOPLATEST,

                                VIOTYPE,

                                VIODUEDT,

                                VIONOTICEDT,

                                VIOAFFDUEDT,

                                VIOAFFDUEDTSTARTDT,

                                VIOKEYEDDUEDT,

                                VIOAFFDUEDTCALC,

                                MAILRCVDDT,

                                KEYDT,

                                RELDT,

                                REQDT,

                                RESPDT,

                                LASTRESPERRDT,

                                DOCNUM,

                                BATCHTYPE,

                                BATCHPROCTYPE,

                                FILENAMEUPLD,

                                FILENAMEEVIO,

                                CLIENTRESP,

                                STATRESPPARTY,

                                TYPERESPPARTY,

                                FINLIAB,

                                FINLIABREASON,

                                CLIENTFINLIABEFFDT,

                                RNTFINBILLEDTOCLIENTDT,

                                FINREIMBURSETOCLIENTDT,

                                CENTRALBILLING,

                                TYPERESPPARTYCHGDT,

                                RESPREASON,

                                SOLDSTOLENDT,

                                SALETYPE,

                                RESPTYPE,

                                BPADT,

                                CCNUMPROV,

                                CCCREDITORDEBIT,

                                CCEXPDT,

                                CCADDDT,