Idle temps don't mean much. It is when the processor/MB/card is stressed that matters. Those idle temps are fine, as I would expect them to be. The card's fan will run slow when it isn't in heavy gaming and picks up speed as needed. You probably saw the fan running at idle and thought it was kinda wimpy. You need to get some readings when gaming or when running a benchmark pgm.
I like to see at least a front and rear case fan if your case has an open top for thermal convection. If the top is enclosed, I'd consider adding a bottom (or even side fan) intaking air. The idea is to get as much air flow as possible in and out of the case; more in than out. Positive pressure.