Hi, chi_ling. Johnny Jump-ups are biennial plants, which means they put down seed one year, rest over the winter, and then bloom the next spring/summer. Your plants will probably do fine outside, although you should insulate the pot by wrapping it with a blanket or bubble wrap, covering it with mulch, or burying it to the rim in the garden somewhere. You may even have a few surprise plants come up next spring, in places you don't expect. The seed pods tend to shoot seeds out in all directions, and the little plants "jump up" the following spring.

Probably only some of the seeds sprouted. the rest will come up next year. but the seedlings will probably be okay, since they will handle temp. of 10-20 degrees F. I had pansies outside this year. it snowed for about a week, and they just kept on blooming! So dont worry about them too much, but keep an eye of them. And if a frost comes, cover them with mulch or clear plastic wrap. But dont worry! Somebody near my house has adult pansies(johnny jump-ups, whatever you want to call them!) growing and blooming right now, and even when it snowed and they were fine!