It is possible to change the entire performance of a bike with gear changes. I run a triple also and originally had a 52-42-30 chain ring on the front with a 13 - 26 cassette. I needed lower gears for some planned rides. The original rings were changed out for a 50-39-26 set. The suggestion of the 26T chain ring came from Barrettscv and has worked fine. Shifting from 26T to 39 is a bit sluggish but it does work reliably. I put together a cassette with a 30T cog. I don't need this low gearing for everything so the original cassette is on an older wheel that is easily swapped out, depending on the ride I'm doing.

My, or anyone elses gearing solution is unlikely to be right for you but you can see that many options are available to you. As has been suggested, play around with a gear calculator to determine what will fit your needs. I like this gear calculator because it is very visual. http://www.gear-calculator.com/#