Yes, getting another pack will effectively double your range. They weigh about 17lbs and cost about $100 from Currie.

Another option is to buy a Ping lithium pack, which is what I did. It's 20aH, weighs less than the Currie pack, and should last many times longer than the Currie pack. I got mine last November for a good price on Ebay when the Microsoft cashback program was at 30%. If it lasts as long as advertised it will be very cost effective.

Note that because of the Peukert effect, the Currie 10aH pack is really more like 6aH if you discharge it in about a half hour, which is what I was doing.