It is good news that one part of the card displays correctly and another part does not. That probably means you have a proper font for Japanese, and the problem is just that one part of your card isn’t using it. Try using the font that works for the back of the card for the stuff on the front.
I believe the two fonts for Japanese on Windows are called MS Mincho (serif) and MS Gothic (sans). Whatever you do, make sure you use a proper Japanese font, or you may end up seeing Chinese variants of certain kanji.