PL/SQL :: Retrieving Data Between two Dates?

I am using Oracle 11g version

create table ORG(Name char(20),Datetime char(45),val1 number);

insert into ORGvalues('abc','10/29/2012 13:00','1.5')
insert into ORGvalues('abc','10/29/2012 13:05','1.5')
insert into ORGvalues('abc','10/29/2012 13:10','1.5')
insert into ORGvalues('abc','10/29/2012 13:15','1.5')
insert into ORGvalues('abc','10/29/2012 13:20','0.00')
insert into ORGvalues('abc','10/29/2012 13:25','0.00')

[code]....

while I am retrieving data between two dates. from table ORG. select from ORG where datetime between '29/03/2013' and '30/03/2013' order by datetime asc*

the output is coming like this,

O/P:

abc 29/03/2012 13:00 1.5
abc 29/03/2012 13:05 1.5
'abc 29/03/2012 13:10 1.5
'abc 30/03/2012 13:15 1.5'
'abc 30/03/2012 13:20 0.00
'abc 30/03/2012 13:25 0.00

[code]....

My problem in above out put is Here I am getting previous year data also at same day and month I want data only between the dates which are specified in query

But here needed output is

*'abc 29/03/2013 13:35 0.00*
*'abc 29/03/2013 13:40 2.1*
*'abc 30/03/2013 13:45 2.3*
*'abc 30/03/2013 13:50 2.1*
*'abc 31/03/2013 13:55 2.1*
*'abc 31/03/2013 14:00 2.2*

Note:my datetime datatype is char

My dear friends actually I am getting data like this date as a string(CHAR datatype) from third party tool.Due to this reason only I treat datetime attribute as string.