[Troubleshooting] GPU Temps

I recently built a new gaming rig for Christmas and I am a little worried about GPU temps. I have a Zotac GTX 570 card (Air cooled). Idle it runs at about 30 degrees, when playing games of varying graphics levels it's maxed out at around 70 degrees. Are these safe temps? If not what is safe? Any recomendations on how to cool it better (outside of liquid cooling). Thank you for any help.