cannot be opened because it is version 655. This server supports 612 and earlier

Question

Hi all.
i get the error like that:
The database '....MDF' cannot be opened because it is version 661. This server supports version 655 and earlier. A downgrade path is not supported.
i also install sql server 2008 with full requirements , when i attached one  .mdf file into database i get the error from look like of above talking error .
How do I fix the problem?
thanks and best regards.