resurrecting my R50p

[geoffs]

Hi new user here.

I was looking around for a new laptop to replace an unused, aging R50p and decided that there's really nothing wrong with it that a bit of tweaking won't fix (except perhaps the weight )
It already has 2GB memory which I believe is the maximum?
I've ordered an Ultraslim HD bay from eBay and will fit a WD 160GB disk to it.
The one other thing I need is a new battery, after 6 or 7 years the original is well past it's retirement date. There are any number of places selling replacement batteries, any particular seller recommended? eBay preferred.

The system currently runs Windows XP but I do have a replacement disk that has Linux installed. The Ultrabay is so I can replace the OS without removing the internal disk too often.

Regards
Geoff