Speed uphill is a function of your power to weight ratio. You need to either increase your power over the time it takes to climb the hill or decrease your weight or both.
As burnthesheep says, increasing power on the bike likely means more of a focus on riding and less on lifting. A simple idea may be to go ride the hill on your own. Do several hard repeats (how many would depend on the length of the hill and how long you've been riding), and try to either bring down the average time it takes to do them, reduce the rest between efforts or increase the total number of efforts (this would be analogous to doing more weight, taking shorter rests or doing more sets in the gym).