Looking at all the inputs and comments over the internet, there seems to be no way to extract the Updated Build number/name/ drop folder name from TFSBuild.exe.
So, i have managed a Workaorund. (Bit tedious, but works)
Push all the output of TFSBuild.exe command to a txt file.
TFSBuild.exe start "TFS Server Path" >> "SOME TXT FILE"
Parse the txt file and extract the line containing value "Updated Build number:" and get the output folder name.
As i know the Drop location where all the builds are dropped, append the foldername and get the files.