Hi, just my two cents worth. I also struggle with strength on the bike and elsewhere and how it translates to power and speed. I too have great staying power, but I finish later than everyone else. I found this online coaching program this fall and started using it and it is making a difference! Here is the link:
www.cyclo-club.com
You can also listen to the podcasts from the same trainer (Graeme Street) for free at :
everydaycyclistpodcast.com

His ideas are very solid and he really addresses the problem of only doing endurance work vs. doing short, high intensity workouts. He's got on the bike workouts as well as resistance training, yoga and core workouts. I am about 10 weeks into the program and I'm really starting to notice a difference. I go up hills in a higher gear than I used to and I feel stronger on the bike overall. Plus my core has really gotten strong. It's not that much money to join if you compare it to the trainer at the gym. I joined a gym in September and signed up for a personal trainer and was very disappointed. I've made much more progress with the online coaching.
See what you think and good luck