Unable to open .sps.bak database backup file with SQL Server 2012 Express edition
That's probably a Sharepoint backup. Restore it in Sharepoint, or ask for a SQL server backup

Your error message shows that you are connected to a SQL 2008 server, not SQL 2012, and that the backup was performed on a SQL 2008 R2 server. You need an R2 server, or SQL 2012, to restore it.