You need to download the latest version of SSDT from http://msdn.microsoft.com/en-us/data/hh297027 (or by clicking the "Get the latest version" link in the error message). SSDT uses a shared component called DacFx, and when you installed SQL Server 2012 on your machine a newer version of DacFx was installed. Updating SSDT will ensure everything is compatible.
Note: Make sure you have a stable internet connection, otherwise you may have issues installing from the web installation and/or the .iso file download.