800 or 1200

Hi guys - I am fairly new to biking, and have done 14,000 kms the past year on my 650 GS single.  So it's time to replace her with either a 800 GS or the 1200 GS.  I do about 70% commuting to the different courts and back and the rest is spent on gravel.  If I buy now, I don't want to sell and buy again in a year's time, so your input will be appreciated!