Also, don't go necessarily by how much you can bench... while the ol' "how much can you bench?" has always been the layman's standard for strength, it doesn't necessarily translate itself into ease of drawing a bow. I've always considered myself reasonably strong, as I've been involved in some sort of athletics my whole life through high school, college and afterwards and have spent more than my share of time in the gym myself...
But, I was shooting in the back yard a couple years ago when a friend stopped by who was a frequent lifting partner. Now, I was and am nowhere in this guy's league, but he pushed me hard and was a great partner. He was a starting Division-I outside linebacker, and could probably throw up close to 400 in his heyday. He just took the title of Missouri Show-Me Naturals last month in his very first bodybuilding contest... The point of all that? He struggled mightily to pull my bow back -- and it was set at 65. He watched in amazement as I sat cross-legged on the ground, held my bow arm level, and effortlessly drew the back slowly and under control.
Practice, practice, repetition, repetition... you get the idea. Being muscle-bound isn't necessarily what's going to help. I know you may not have been implying that, but the point is that it's just going to take shooting -- a lot.