How to open .mdf file of version 661 if server support only 655 and earlier?

I was using one forum source code with VISUAL STUDIO 2010 where its .mdf file does not support with my visual studio database version,
giving error :


The database 'E:\ASPNETFORUM_TRIAL\APP_DATA\FORUM.MDF' cannot be opened because it is version 661. This server supports version 655 and earlier. A downgrade path is not supported.
Could not open new database 'E:\ASPNETFORUM_TRIAL\APP_DATA\FORUM.MDF'. CREATE DATABASE is aborted.
An attempt to attach an auto-named database for file E:\AspNetForum_Trial\App_Data\FORUM.mdf failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share.

how to solve can any suggest?