You do need drivers indeed, and I'm afraid they're not available for XP. Maybe you can install windows 7 on the Dell laptop, or find a cheap used one with windows 7 already installed. I'm using a W7 Dell laptop every week together with the XR18 to multitrack our bandrehearsals. No problems at all.
For recording to your iPad you could use Auria. It will record multitrack straight out of the XR18 and export Reaper compatible files according to this thread:
https://forum.cockos.com/showthread.php?t=183592
Good Luck!