Dunno if this'll help but I got wireless working today on my HP dv5046ea running a bcm4318 card with ndiswrapper on 64bit Dapper.
I pretty much ran the same commands as you but I blacklisted the bcm43xx ubuntu driver in /etc/modprobe.d/blacklist before installing the 64 bit one. Once I installed the 64 bit driver and ran ndiswrapper -m I rebooted and entered my ssid and wep key in the network settings and it works as good as it does in windows. One thing I don't get though is when I ran ndiswrapper -m the card was called wlan0. After the reboot it was called eth1. Absolutely no idea why, but it works so I'm not complaining!
iwconfig reports
lo no wireless extensions.
eth0 no wireless extensions.
eth1 IEEE 802.11g ESSID:"stevew54g"
Mode:Managed Frequency:2.462 GHz Access Point: 00:11:50:4F
F:7D
Bit Rate=54 Mb/s Tx-Power:25 dBm
RTS thr
ff Fragment thr
ff
Power Management
ff
Link Quality:100/100 Signal level:-67 dBm Noise level:-256 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:122 Invalid misc:57824 Missed beacon:0
sit0 no wireless extensions.
It's taken a while to get this running trying FC5 and Suse 10.2 before settling on Dapper.
