That being said is NOT close to therefore, 'that being said' is closer to 'however' or 'but' which is pretty much the opposite of therefore. Therefore, is used after making a statement and followed by a declaration backing up the statement in a run on sentence. For example.
"I am from England, therefore I speak English"
That being said is used to modify a statement, in the same way as but or however is used
"I love London, that being said I could not live there!"
Cheers,
Chris