Hej
I assume you mean that you want to fly out 08JUN and return 18JUN.
Either you buy a ticket to EWR or ORD and then add a doemstic ticket. If you want a through fare on Star Alliance US seems to be cheapest with SEK5500+taxes. Cheapest fare that I could find was AA with SEK3400+taxes or KL with SEK3500+taxes.
SK starts raising their fares around 20MAY and then increase to "summer fares" 09JUN this year. Effectively meaning that after 20MAY it becomes expensive. American carriers go to peak season around 14JUN.
Note that the deal with SK for cheap summer prices ends 15MAR.