Bob,
I use SATPC32 to drive both antennas and radio. Using my FT-847 with the appropriate uplink and downlink converters, operating mode LU and VS on AO-51 is no different than VU or UV on FM. As Erich mentioned, you can drive two different radios easily enough.
After trying several rotator interfaces over the years, I am currently using the Labjack with the Piggyback board. (At the time, it was completely plug and play. Northern Lights Software discontinued the Piggyback board, however, building an interface is easy for both the original and new Labjack data logger. See the accessory information at the bottom of the SATPC32 download page.) It takes its power from an USB port. I use an old powered hub for it and some other connections which can get by with USB 1.1 speeds, as it provides a bit of protection to the computer.
Another good alternative is the LVB tracker. It just about stole the show at the AMSAT booth at Dayton. Some assembly required, the amount depending on features needed, but none of it is hard, and it will easily work with a serial or USB connection, and will of course drive your rotator controller. Works fine with SATPC32, of course. AMSAT-UK has some nice pictures at http://www.uk.amsat.org:8080/shop/Hardware/lvb_tracker_kits.php AMSAT-NA and others have been considering putting together a full up kit, and perhaps some assembled units.
There are many alternatives, and of course SATPC32 supports just about any tracking interface you could desire. My suggestion is to get one of the newer designs because they have much higher resolutions on the ADCs than the older ones. More than you can actually use, really, but room for growth. Also, USB connection is a plus, since serial and parallel ports are rapidly going away, and the USB to serial/parallel converters are often less than satisfactory. Of course, if you come across a TrakBox, FODTrack, etc, etc, at a flea market, it might be just what suits you.
FWIW,
Alan WA4SCA