What is the actual capacity readout in mAh? 99% sounds like, "No, nothing is wrong with your battery." 1.5 hours sounds like there is something wrong, unless you are running the computer excessively hard during that 1.5 hours.... like with both wireless radios on, full screen brightness, and lots and lots of DVD and HD activity, yes, perhaps you could push all the way down to 1.5 hours, but otherwise that's too low.
But then your capacity should not list as 99%. Note that capacity isn't the current charge level (like when it says the battery is 99% charged up at the top of the screen). Capacity is how much charge the battery actually holds. You can find it out using the ioreg command at the terminal or using something like Coconut battery or the system profiler.