If you're just starting hills can be hard. The best way to improve hill climbing is to just do them repeatedly. If you have sufficient gearing, it's more efficient to just spin up the hill; 70-80+ rpm works for me. Standing is great for stretching the legs and powering a bigger gear up tougher hills. In the past I'd usually spin up a hill but on longer rides (60+ km) I find standing up helps me stretch my back and relieve butt-aches. Interval training on hills will help you improve as well.

When I first started road biking about four years ago some of the bigger hills just killed me, even with 34/27. Now I take those same hills with a 34/23 and find I carry more speed with a lower heart rate as well. Just keep working at it and make sure your seat height is properly adjusted.