I would wait until after the danger of frost. Once they're planted and established they should be fine year to year. I'm in Zone 6 and mulch mine through the winter just to be absolutly sure they'll make it.
I ordered mine through the mail last year and they got here too early so I pre-planted them in a small box planter inside then transfered about a month later and they did very well (I have to thin out at least 100 this spring) Good luck with them
I would get them in the ground and have a sheet at the ready, when frost is predicted. If you think you will have many more frosts, maybe plant them and cover them with straw for a few weeks...
I got my started strawberry plants from a nursery too and planted them in a container last Friday. The leaves are already opening up. I set them outside once the sun is up and I bring them in before night falls.
Got my potatoes growing in a sack too. They seem to be doing fine as well...I just bring them in before night falls.