Booking with multiple airlines, and travel agents

beklemmung

Using a site listed in another thread in this forum (itasoftware.com), I found a roundtrip booking from NYC to Delhi through Heathrow for $894. The problem is that the first leg, from JFK to Heathrow, is with BA, and the second leg from Heathrow to Delhi is with Virgin.

Since itasoftware's site doesn't do the actual booking, is there a way for me to book these flights online at the price that's quoted? As far as I can tell, an "online travel agent" is someone like travelocity, expedia, orbitz, etc, and if I search for these same flights using those sites, it's considerably more than $894. Likewise, when I try to book the flights individually on BA and Virgin's websites, it's more expensive.

If I were to print the itinerary out and take it to a travel agent in person, how much should I expect to pay them to do the booking for me?

Thanks in advance for advice.