Restore append?

Using SQL2008

Here's my situation: I have a backup file from 2012. I need to move those data into the current production db. I figured I can restore to a new temp database and insert data from that temp database. However with hundreds of millions of rows, this is probably an impossible task. And I need it to be in a same database because the 3rd party application cannot do a union.

I know in Oracle I can use the utility impdp / expdp with APPEND to restore tables instead of REPLACE. Is there a way I can restore append to the current production db in SQL2008?

If not, does anyone have any suggestions on achieving this?

Thanks,