I had also enquire from POSB and this is their reply
"Dear Mr Chua, Thank you for your enquiry.
Please be advised that the special 6 months Bonus Interest of 1% p.a applies for those who had register for the early birth special by 31 October 2014 and open a POSB CDA with us by 30 June 2015 to get. This special interest will be credited to the POSB CDA by 31 August 2015.
You will be able to transfer your CDA from other instituition to DBS/POSB Account by 2nd quarter of 2015 through the website of Ministry of Social and Family Development."
As of now, the authorise banks for CDA are OCBC and Standard Chartered. So i presume that we are able to transfer the CDA to other Banks during the 2nd quarter of 2015 via the MSF website.
Hope this helps