So.. you can't handle the hills at the gear ratio you have, yet you are considering getting heavier gear ratio so you don't spin out on the downhills....
Sounds to me like the problem is just that the fixed gear doesn't work for the terrain you ride.

I live in Atlanta, very hilly, and it baffles me I see people on fixed gear or single speed bikes, struggling.

I know, I know, all your hipster friends have single speeds as well, and that's what's cool. But there's nothing cool about walking your bike up a hill buddy.