This is my first year of growing strawberries and what I've done is pinned down the runners at the buds, let them root and grow then cut them from the main plants and potted them up.
Goodness knows if what I've done is right but I've doubled my plants for this year - if they survive :)
Good luck with yours!!

Sounds good to me, as long as they are strong young plants by sharp frosts. If they are still a little puny, they may be better off in a cold frame or unheated greenhouse over the winter. If you are talking about barely rooted runners, I would make plans to keep them in a heated greenhouse--a little on the cool side--through the winter.