ADF7020-1 question

I want to be able to offer two frequency ranges, one being ~600MHz and the other being ~900 MHz.  I'm wondering if I  can expand the range of the 7020-1 to get up to the 900MHz.  It looks like the -1 part was designed to hit the lower frequency ranges and that the upper end of the VCO was affected by this.  Am I on the right track?  Is there another transceiver part that will cover the two ranges mentioned?  My data rate is about 50kbps.

Thanks,

Tim