Is your seat set up to the proper height? I'm just curious about the overall fit. Also, before you invest in a bike that may be 10 pounds lighter, take 10 pounds of books out compared to what you normally carry and see if you can make it up the hills. If you can't, a 10 pound lighter bike won't help. Suspension can drop the efficiency a bit but you lose more from suspension in the rear.

I live in a suburb of Pittsburgh and have hills like yours and worse. There are some near me in the 16 percent range and my LHT can make it up loaded. I hit one section two days ago that was 18 percent for a short ways. My old 1984 Ross Mt. Rainier can as well and it is a heavy bike. I often load mine down with 35-50 pounds and at times more. I took a propane tank home from Lowes the other day along with other odd an ends as well. Thankfully the majority of the hills I ride to run errands are around 6-8 percent. I feel your pain.

What I am saying is that you might not want to waste your money trying to drop 10 pounds from the bike, it may not help. 10 pounds won't make or break you on a hill. There is something to be said for geometry but still, the engine will be the biggest factor especially considering your gearing.