Update on this:

We tried to put a 28 on my bike, only to find out my derailleur couldn't handle it. Settled for a 26 instead. I headed out yesterday to try the hill again, although I wasn't super confident because it was about the hottest day of the year. Started up it fine in my easiest gear, until I hit the part where I always have trouble. I was doing a sharp little zig zag with every pedal stroke, and then I briefly stood. Now I'm not sure if this hpapened when I was sitting or standing -- DH says I must've been standing -- but the front wheel started leaving the ground, which is when I freaked out and unclipped.

Gahhh this GD hill. The section I can't handle is only like, 20 feet long, and its not like this hill is even part of my daily route but its so close to my house and it is killing me! Anyway, does the fact that my tire was hopping off the ground change anything technique-wise that might help me?