There is no "trial" version of the SDK. If you mean that you have the trial version of Crystal 2013, it does not come with the updated SDK. Instead, you need to download and run the "Install Executable" for Crystal for VS SP12 from here: http://scn.sap.com/docs/DOC-7824. This will integrate the new SDK into Visual Studio. The other downloads on that page are for the various types of runtime installs that are available.
After you have this integrated into VS, you'll need to change ALL of the CrystalDecisions references in your project to the version 13 references. You may also need to uninstall the old Crystal SDK in order to get it to work correctly.
-Dell