Al-xc:
60 second efforts are not sprints. Sprints only last 5-15-30 seconds at the most. 60 second efforts might be part of a good program, but not the basis of one. You have improved on longer climbs which is good. I'm guessing you are doing the 60 second efforts to improve climbing speed.
Sprinting uphill is one of the best ways to get faster on climbs. Sprint as hard as you possibly can which should only be 10-15 seconds or so, then completely blow up. Pedal however easy and slowly you have to in order to recover, then sprint hard again. Repeat until you get to the top. Hill sprints are one of the hardest forms of training.
Eventually, in a few weeks or next month, you will notice you can climb faster or climb at your old speed with much less effort.
Cycling is the hardest sport on earth. If you want to be fast, you have to train very, very, hard. Someone you compete against will!!!
Good luck!!!