If your temp table and your real table are in the same database or on the same server you should use an Execute SQL Task to do this. Your code would be something like this:

Update real_table

Set columns = TT.columns

From

real_table RT Join

temp_table TT On

RT.unique_key = TT.unique_key

Insert Into real_table

Select

columns

From

temp_table TT

Where

Not Exists(Select 1 from real_table RT where TT.unique_key = RT.unique_key)