• You can not get your space back on that way.

    The only way I know is that you have to restart SQL server services. But You really have to read BOL about TempDB management.

    I will recommend you start from here.

    http://blogs.msdn.com/b/sqlserverstorageengine/archive/2009/01/04/managing-tempdb-in-sql-server-tempdb-configuration.aspx