I am in the same boat. My DD2's preschool pick-up time is 1:00, and by the time we're home (if we high-tail it out of there), it's 1:15, and DD3's down by 1:30. But she also usually wakes well before 7 am, so that is a REALLY long morning. Pretty much we've just had to suck it up and get home as quickly as possible. Occasionally I'll pick DD2 up a bit early so we can shave 15 minutes off, but it's a hard sell, and it's not much better, anyway.
Does she go down easily for the later afternoon nap if she cat-naps during the morning drop-off? If she does, I'd probably keep doing this as long as you can, even with the later bed time. If she sometimes resists it, though, then you pretty much have no choice but to keep her up. Does she transfer from the car reasonably well? You could let her fall asleep in the car at pick-up time, and then transfer her to bed when you get home... which has never, ever worked for me, but maybe it would for you? Just a thought.