You can also use NTLDR to load your system. The grub img needs to be in C:\\ and boot.ini should include an section to boot rhel.
You could also re-install RHEL after XP and write grub in the MBR at the end of installation. It should take care of the XP installation by default. (It SHOULD, but I don't use RedHat , so, ...:))
BTW, use 9GB as the swap is a waste. You know that, don't you? :p