We need to know which broadcom wifi card it is. You can probably get that by entering lspci to a terminal and looking for the line that describes your card - copy that line to your reply.
Note: you can use RH tech support, which you paid for with your RHEL5. If you are unwilling to use commercial support, you should really use a non-commercial distro. They tend to have better HW support anyway.
http://tuxmobil.org/hp_compaq.html
... includes entries for nx9010 in archive.