Shavua tov (שָׁבוּעַ טוֹב) is Hebrew for “good week,” and it is the customary wish said on Saturday night after the conclusion of Shabbat.
It is customarily said following Havdalah, which marks the end of Shabbat, as well as whenever we greet each other or say goodbye for the remainder of the evening (and even later).
Its Yiddish counterpart is ah gutte voch (א גוטע וואך), which means the same thing.

And: "eine gute Woche" in German, which shows how similar Yiddish and German can be. In some regions of Austria one can say: "A guate Woch'n"
I thought it resembled German a bit! ;)