Can timer be configured for interrupts every 50uS

I am trying to get the IRlibrary working. It requires an interrupt to occur every 50uS.

The defines for the available clock selections (RTC.CLKSEL register) are:

RTC_CLKSEL_INT32K_gc
RTC_CLKSEL_INT1K_gc
RTC_CLKSEL_TOSC32K_gc
RTC_CLKSEL_EXTCLK_gc

Which clocks work for the WIFI Rev2 and what are the frequency(s) of the clocks?

I have used the 32K clock, which operates at 32,768 Hz. It providing a max interrupt rate of 1 every 30.5176 uS. I don't know how to adjust it to a rate closer to 50uS. Any ideas or are any other better clocks available ?