UK software update, help required

I've just replaced the batteries (NMH) with a much better set and now have a range of pretty much 30 miles.
To give the batteries the best chance of being long lived, I guess I need to update the software to enable lower amperage charging if at all possible. Problem is, I'm in way over my head already and being a mac person, working with PC's makes me nervous. I can hire a connecting cable but really need some assistance installing the new software.
I'm happy to pay for this service and transport the bike anywhere within reason, can anyone help?
I've spoken to a couple of people but they are unable to help
Any advice appreciated
Simon