It's called Midiox and it allows you to midi data dump your 01W into the PC. So you need to be able to connect by midi to your PC to do all this.
On your 01W press the GLOBAL button and go to Page 8. It's called the Data Dump page. There you will see an option to midi data dump your 01W. Set this to ALL but don't dump the data just yet. It's important that you have navigated to the page and are ready to dump the data before you setup the midiox app to receive the signal. Otherwise it will pick up your button pressing and navigating on the 01W as SysEX data.
Anyway so your 01W is ready, now you launch Midiox. Go to View and then to SysEx. A window will pop up at this point and you can select SysEx from this window followed by Receive Manual Dump.
Once you do that, get your 01W to send the midi dump. Once complete, save your dump so you can send it back to your 01W after you change the battery.
Actually, I would recommend doing a test before you change the battery by sending the file back to the 01W just to verify that it accepts it and all is good.