If you want to get better at hills you have to do them more often and hit them a little harder each time. When you are doing them, stand every so often. Dropping your cadence to 80 or below is totally normal for hills....mine is probably 70rpms.
Do some hills by yourself and get into a comfortable gear so you are climbing without blowing yourself up. Don't worry about the cadence or your speed, just realize that going up a hill is harder than the flats....it's supposed to hurt more. You will get stronger and go faster up them as you do more of them.