Wanting a Prewar apartment this summer - tips?

Moving in June or July. Well, I hope so.... I like my current apartment, but over the railroad layout. Blah. I want prewar charm, nice space and those special touches. I REALLY want a clawfoot tub. Is that so hard to ask? And french windows. Why does this seem so difficult in my search? I don't want to live in Harlem, I'll stay on the Upper East Side if need be... but I want to go downtown. I'm willing to pay good money. And I'm trying to lock in something now if that's possible so I don't deal with the summer rental traffic jam. So any idea on how to lock something now and where to look? I always imagined those village apartments to have the features I'm looking for, but even under searches for up to 3k.... I'm finding zilch.