You have a bail out gear, but refuse to use it because you want to struggle up a hill? The goal is to be comfortable when you climb. Use the saddle and bar to direct the energy to the crank. Stay smooth. Get a smaller front chain ring and toe clips if needed. Leg strength will come with time if you maintain good riding technique. It takes months to pickup 1-2mph on a climb.

My Cannondale has tight geometry, but I can still squeeze in 28C. It may be a little tight at the back. Do not over-inflate the tire...no more than 80psi if you're 150lbs and ride 28C or larger. You don't want to bunny-hop the bike. A tiny head wind will wipe out any minute edge in tire performance. Aero is not a factor when you climb hills.