Kid-friendly cafe near Gare D'Austerlitz?
 

I have 90 minutes to kill between a Eurostar arrival, and a sleeper train departure from Gare d'Austerlitz at 2050 in January. 1 adult + two kids + luggage.

I think if we get the metro straight to Austerlitz, we'll probably be waiting for an hour, and it's not the most welcoming place. Can anyone recommend somewhere relatively comfortable and convenient to wait? Somewhere near Gare du Lyon + then cab over the river? I'm thinking of somewhere the kids can have a hot chocolate and toilet stop if necessary. I'd even accept a Starbucks, but they all seem to close about 20:00.

Thanks.