I understand your problem! I have Win 98 on my laptop to read my cards and then bring them over to my XP machine via my network. Here is a link to info to work with your Sram card and XP. I have not tried it, just read it. Good luck.
If you were looking to upgrade it would be well worthwhile taking a look at the Agleader PF3000 this unit would replace your existing box but still use the same yield and moisture sensors and it uses ATA memory cards that XP reads without a problem using low cost card readers. If you do manage to get XP to read Sram cards I'd like to know as it's something I've never managed to do yet. I'll try out the solution offered in the other posters link and see what happens.