Do the games you play feel fast? There have been a lot of instances where 3dmark scores are lower than supposed to be while the owner didn't have any problems in games. I would suggest you play some games and see if they run smoothly and then worry about 3dmark scores given your circumstances.
Also, see if you can view Details of the benchmark. Although you can't get the score until you log online, I believe there is a way to view the actual benchmarks you got in each test. If you provide those, I am sure someone with similar specs can provide guidance if the 3dmark score you are getting is "normal"