Yamaha DTXpress/DTXplorer/DTXtreme

I have been using a Yamaha DTX Pro V2.0 (via a CD Player & headphones 
only) for the past 2 years. It's for home use only and I live in
the 
UK. I think it's great (so do the neighbours!). 

Reading the "'phone book" size instructions, the battery
that 
maintains the memory, only lasts for about 2 years, so I am getting 
anxious.

1)      I don't want to loose the drum kits that I have
painstakingly 
built up. Can I back up to a PC? I have an up to date computer, 
complete with a Sound Blaster Live 1024, (which I don't know how
to 
work), and I'm afraid I don't understand Midi either (but I
am 
willing to learn – if necessary)

2)      I need to know how I get the battery replaced. Can I do it 
myself? Or can I get it done (cheaply) in the UK ?

Can anybody HELP? Please.

I wrote to Yamaha in the UK but havn't had a reply.(if you are 
listening Yamaha - Shame on you!.......if you are not listening - you 
should be!).

Please be specific if you can, (step by step instructions would be 
great) as I am not very technical, but still enjoy drumming after all 
these years!

By the way, what's the difference between the DTXpress and the
DTX 
Pro ?

Thanks

Born Again Drummer