Hi Rajat,
Take a look at More on System Landscape Directory. There are several blogs there that talk about migrating from one SLD to another. (Especially Switching between 2 SLD Systems in Sync with an LMDB or a 3rd SLD).
It sounds to me like you changed the setup for the data supplier side, (so your new SLD has the correct data) but you haven't changed the SLD-client setup of the portal (so your portal doesn't know to look at the new SLD for data). Take a look at this SAP help document, Synchronizing the System Landscape Directory with the Portal, and see if you can find what you need there.
I hope this helps!
Best regards,
--Tom