once u put it into ita and select the flight u want.. goto the airlines actual website and do it. it will sae you booking fees

You can’t buy through ITA; you’ll have to hunt down the fare elsewhere.  In some cases can turn out to be quite difficult, but sounds like you’ve already found it.

Orbitz uses the same engine as ITA so it’s one possible choice if you are trying to track down multi-airline itineraries in particular. There’s never any guarantee you’ll be able to get the same thing you see on ITA – sometimes that price is out of date. Kayak gets Orbitz prices when it does its sweep of various sites, so it’s a good place to start looking.

Keep in mind that even if one of you gets the price you see on ITA or elsewhere, the other may not be able to do so. So for example if you decide to buy from Orbitz you should first get price quote for two people togteher to make sure there are two seats available at that price. Then go ahead with your separate bookings.
Yet again, there is no 100 percent guarantee, and to be completely safe you may consider booking both ticks together and writing one another a check.