While lower temp is always desirable, peaking occasionally to 80C is not going to hurt anything as long as the fan(s) spin up accordingly. There's not much you can do to the card itself other than clean the old thermal paste off and put new on... if the old stuff is dried out. Was the card new or used?
But you can provide as much airflow thru your case as possible. That may help. Do you live in a hot area? What is the ambient temp where the PC is located?