Great news. NppToR 2.3.0 was just released. There two noticeable improvements. First NppToR now handles passing Unicode strings for international characters. Since Notepad++ is Unicode now, NppToR supports it now as well.
Second there was a problem with reading the registry for 64-bit versions of Windows Vista and Windows 7. That has now been fixed and the R-home and Notepad++ directories are read from the registry as they should be when running NppToR on a 64-bit system.
Of the less noticeable changes, the clipboard restoring is managed a bit better and there is now a silent install option.