sed/awk changing values

Can somebody help me out and provide me with a SED or AWK solution that converts TO_DATE CLAUSE -> TIMESTAMP

I need to keep the PARTION value (HISTORY_20110417) and DATE/TIME value (2011-04-18 00:00:00) the same for every line

 
PARTITION HISTORY_20110417 VALUES LESS THAN (TO_DATE(' 2011-04-18 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN'))
 
PARTITION HISTORY_20110417 VALUES LESS THAN (TIMESTAMP' 2011-04-18 00:00:00')
 

Thanks in advance to all who answer

Is Perl OK?

perl -F"," -nae '$F[0]=~s/TO_DATE\((.*)/TIMESTAMP\1)\n/;print $F[0]' file

or shorter:

perl -pe 's/TO_DATE\(([^,]+).*/TIMESTAMP\1)/' file

bartus thanks

using nawk..

$ nawk -F"[(,)]" '{print $1"(TIMESTAMP"$3")"}' file