In addition to the great advice people have given you...I would Just keep doing hills over and over. Make them a part of every ride. Start with hills you're capable of, then add steeper and/or longer ones. I used to hate hills, but my husband loves them. So he takes me on rides that he likes, which usually have anywhere from 1800-2200 feet of climbing in about 40 miles or so. Some of you may be familiar with the Chilly Hilly ride we have here in the northwest, well my husband likes to do that ride and add on a few other streets so that it is hillier!! Now I often don't think a ride is that hilly unless it's rolling hills with a few good 8-12% inclines over a couple miles. Every time I do hills I initially thought were hard, they feel easier and easier. It's really just a matter of building up your muscles and your lung capacity. Good luck. It will get easier.
-Jessica