I would take the bike back to the dealer and see if they could swap the rear cog for a larger one to reduce the gearing... my 3 speed road bike runs a 48:20 which gives me a 49/65/86 which works for a vintage sub 30 pound bicycle and a skinny old guy who likes to spin. I would not want my main gear to be any lower than 65 gear inches which is a little lower than what I run on my fixed gear and ss bicycles.

For what is basically a townie a lower gear range would be better and I'd go and see the dealer and ask if they can install a larger cog (18 or 20) to give you a more suitable gear range... this gearing issue is becoming a common complaint with many new 3 speed owners.