Oh BTW the Arduino defaults to 100kb/s for I2C or you can set fast mode which is 400kb/s.
The AS1130 can work at 1Mb/s but you'll have to bit bang at that speed...or get a compiler that will do it automatically. eg CCS C allows:
#use I2C(master, scl=PIN_B0, sda=PIN_B1, fast=450000)
//sets the target speed to 450 KBSP