You could pin them down into small pots if you wanted to keep them. Wait until the runner has produced it's first set of leaves and then, using something like a straightened out paper clip, pin this down to the soil. It will take a couple of months to produce strong enough roots to cut away from the main plant but that is the next step. Alternatively, if you don't want to grow them on then just cut off at the crown.
Strawberry plants usually lose their vigour after three to four years and need replacing then anyway. so if you like this variety then you will have to do this sooner or later.

Good luck with them and one more bit of info, strawberries produce enormous root systems and will do much better in the open ground if at all possible!

Thank you for the advice, I'll give it a try!