Adobe Camera Raw 6.7 is the newest version of the plug-in that you can use with Photoshop CS5. Here is a link to the download:
Adobe - Adobe Camera Raw and DNG Converter : For Windows : Camera Raw 6.7 Update : Thank You
However, your camera is not supported by that version of Camera Raw. If you want to continue using that version of Photoshop and Camera Raw then the DNG converter is your only alternative. The DNG converter should work without a problem. But you need to be aware that the converter works at the FOLDER level. When you use the DNG converter you need to choose a FOLDER containing your raw images but don't open the folder. If you open the folder then you will get the message that there are no images to convert. If you want to just convert a single image, drag/drop that single image onto the icon for the DNG converter with the converter closed.