I agree with Darkheroz. I found that my battery life improved after 10-12 cycles too. I've been told that it takes a few cycles for the battery to perform properly.
So my advice is to wait another week and see.
Others here have been quite critical of the battery as a whole, so I thought I'd throw in my two-penny's-worth.
My battery often lasts longer than 5 hours, but I often have wifi off. Most of the other posters here seem to always have wifi on. I use my MBA for work mostly, and I don't want to be interrupted by emails every 5 minutes, so I don't need it on all the time.
Apple's website claims you can get 5 hours wireless web browsing with brightness set at 50%. I've never got that when I've tried it, but I've learned to take manufacturer's laptop battery claims with a pinch of salt.