Does anyone know whether there are pre-paid taxis available at the airport in Lima? If yes, how much is a ride from the airport to the Miraflores area?

Also is there an ATM at the airport for obtaining local currency? Same rates/fees as ATMs downtown?

Finally, how safe is it to walk around Miraflores / Centro areas around 8-9pm on weekdays? 'Safe" meaning what are the chances of being mugged / robbed?