Maybe you know the following prayer already, but if not, it's a very powerful one from which people have seen wonderful results. And it's never too late!
It's from the prayer collection called Tefillat Chana Hashalem. It is one of the many prayers you can say after lighting Shabbat candles (pg. 17), but you can also insert it at the end of Shemoneh Esrei or after giving tzedakah or just saying it on its own.
Compassionate Father, may You grant me sons and daughters who are Torah- and mitzvah-observant. And help me to provide them with God-fearing teachers, guides, and educators who give education in the way of the Torah and the tradition. Amen.
Av Harachaman, zakeni b'vanim u'vanot shomrei Torah u'mitzvot. V'azreni l'hamtzi lehem melamdim, madrichim, u'mechanim yirei Hashem hanotnim chinuch b'derech haTorah v'hamsorah. Amen.
אב הרחמן. זכני בבנים ובנות שומרי תורה ומצות
ועזרני להמציא להם מלמדים, מדריכים, ומחנכים יראי השם הנותנים חינוך בדרך התורה והמסורה. אמן
(And just so we know really know what we're saying, the Malbim defines the following:
melamed: One who teaches those who don't know
madrich: One who teaches those who are unable
mechanech: One who habituates them little by little)
May the above tefillah be answered l'tovah for all our children.