wireless b and g compatibility issues

I have an issue with my notebook which has a b/g wireless card built in. It connects to my wireless access point at only the b speed. The WAP I have is the Linksys 4400N and I have changed the settings on it to G/N mode only. I don’t know what’s going on but my notebook is still only connecting to it at max speed of 18Mbps, which is slow considering.

I have even changed the wireless mode settings of my notebook to 802.11g only.
I get an “excellent” signal strength and I don’t understand why the connection is still so slow.

I have the latest drivers installed according to driver detective so I don’t think it’s a driver issue.

It’s a real pain considering I stream DivX video across the wireless connection.