WDS - Client network card affinity

I have a WDS (Wireless Distribution System) setup at Home. router 1)
is primary Buffalo , router 2 ) is Linksys both running Tomato
firmware
Have a Thinkpad laptop.

Setup works great except with 1 hitch. My Laptop's Wifi card does not
automatically switch to the strongest AP signal. IT still holds on to
the original router's connection and so Im getting low conn speeds if
I move around. I tired setting the roaming to aggressive
but no luck.....

Thoughts?