That will change the more you ride.

I sucked at hills all last year, but this weekend I went on two 20 milers with the local team/club, with the racers. They were going slower for my benefit, and they usually beat me up the hills, but I was climbing so much better this year after a winter of boot camp. Sometimes if I could anticipate and get a downhill first, I could get out ahead of them and beat them to the top (I outweigh all those skinny racer boys by about 40 lbs, so I coast fast).

A couple of times, I was SOOOOO happy to have my triple chainrings, so I know what you're going through. On a normal ride, I probably wouldn't use the granny much, because I wouldn't be in a hurry to get up to catch up.

After all I've read in this thread, I think you could use smaller gears, but you wouldn't need them for long. So go with the cheapest option (cassette, I think), and ride lots more, working up to better fitness.

Karen