I am getting error while restoring FileGroup on SQl server 2012
The database engine thinks you're trying to perform a piecemeal restore using the UI.  This is the formal name of restoring individual filegroups.  Sadly, it requires you restore the entire database to maintain transactional consistency (which I don't think you want to do in your scenario) and since you're not overwriting the database (as identified by Pinal Dave's answer), you're getting this error.

If you're only trying to restore that one table, you've got a couple of options available, as follows:


You can restore the database as a different name and then copy the data from the restored copy into the working copy.
You can store that table in a different database and if you need to revert that table, restore the database it's contained within.  Of note, you are unable to maintain Referential Integrity between tables stored in different databases without some trickery (e.g. Triggers).  This may not be a problem now, but it could crop up issues in the future, so just be aware of this if you do separate out this table into a different database.