Taking Database backup for every 4 hrs in SSIS

Question

hi..
i'm trying to retrieve the data from database using ssis package..
database name is employee which contains 48 tables and it is around 20GB of memory.. it is a production
database..

now what i want is to retrieve the data for each four hours..
i.e i want to execute the package for every 4 hrs..

now what i did is i have taken a database transfer task and from the
source i.e production database i want to transfer to my database
which works fine..

but what is the problem  here is for every 4 hrs whole DB is replaced in my system
i've given overwrite TRUE..

Here user enter the data into database for every 4 hour is minimum 10 MB of data..
instead for replacing the whole database for every 4 hrs  is there any
solution that what user enter data into database only that much amount of data  should be append into my system.. is it possible 

please help me..