You need a resistor, period.
You need a transistor to switch the IRLED when giving it a better power source. You'd see some improvement powering the IRLED with the 5V pin's 200mA with an output pin controlling the transistor.
You'd see the best range giving that IRLED 800-1000mA with a proper power supply and if you keep your signals at <1% duty cycle. Read the datasheet.