I play at those same settings except also 2xAA and at 1360x768 on an external LCD.
I did a bunch of tests with the Couter Strike: Source "Stress Test" that might help see if you are getting normal FPS, if mine can be considered "normal"
Here is the original thread http://www.notebookforums.com/thread163748.html
And here is an exerpt of the important part:
"Do the "stress test" in CS:S and see what the average FPS is. I just did mine and it was 48.61. Not awesome but still very respectable and smooth to my eyes. I am not sure if the video settings effect the frame rate so I will try again at lowest settings just to see the entire range of FPS on my system.
With all options at low or off, I got a 139.71 average FPS. Do both tests and compare to see if there is a difference. At least this will confirm that the video performance alone is ok or is the main problem."