Korg Poly800/EX800 Users

Hello, I'm new to the group and new to synths. I just got a Poly 800 
and needed some basic advice. Here are my questions:

1.) Since I bought this used should I replace the internal battery 
right away? And will I lose the memory if I plug it in before I pull 
the battery.

2.)How can I back up my program? Can I go straight to tape from the 
output of the Poly or do I have to go MIDI out to my PC? If I have 
to use MIDI can I use one of those USB Midi interfaces? And do I 
need to use a program such as Midisoft to handle this?

3.) If I need to restore the program can it be done out on a job? If 
so what would be the best way and how long does a reload take?

Thanks in advance
Tim