You say you have the booklets in hard copy. How many copies did you have printed? What other methods of selling the booklet are you contemplating? Do you believe those other methods will be sufficient to move all the copies of the booklet you have?
If you think you can sell them all through other means, then the time, effort and money required to build an ecommerce site might be better spent on tackling those other channels you've already identified.
If not, you need to find some other way(s) to sell them. Ecommerce could be one of those ways. Follow Taviuss' suggestion to brainstorm others.