They generally DOWNGRADE models over the year, not upgrade, in order to keep the price from increasing. While Tiagra is higher level component than Sora, I'm not sure how to compare 2010 Tiagra to 2013 Sora. I'm not sure how much better general bike specs have improved in just three years. Have you tried bargaining for the 2010 mode? You could offer 25% off and see what they say. Bartering for 20% off might be a good compromise.

Looking at the specs.... it is difficult for me to compare. The 2013 is 8 speed and the 2010 is 9 speed. I think I would take the 9 speed as it's more popular/common than 8 speed (or so I've read on the forums). As for triple vs double, it will depend on the range of gears and the spacing. There are lots of gear calculators out there; I like http://www.gear-calculator.com. Check the high and low. If you are going to do hills, lower gearing may be a benefit.