It can be modified to work at a higher frequency. The capacitor that opperates the frequency just needs to be modified from 1uF to another value. The capacitor is connected to pin 2 labeled Cf. There is an equation in the data sheet that will allow you to calculate what size cap you need.
You can also get it from microchip as a free sample. The max number of parts is 5, just order 2 or 3 so you don't look like a mooch. I always order at least 2 so that if something goes wrong with the first one, I don't have to stop working while I wait for a replacement in the mail.