Is this idle, or when the GPU is under load, like playing a game or running a benchmark? 68 degrees would be a normal load temperature for that kind of card. If that is your idle temp, yes that is definitely on the hot side.
A number of things can cause high GPU temperatures. The fan may be clogged with dust, or not working at all. Open up your case and check to see if the fan is clogged with dust. Also check the your case vents, if they are clogged with dust that can cause high temps for the whole system. Clean out the dust and see if that helps. Poor airflow in the case can also cause this problem, in which case you may need to add some case fans. If your GPU has a passive cooler (no fan) a PCI slot fan placed directly under the video card will definitely help keep the card cooler.