Vista - how can I increase default buffering in Windows Media Player

Hi all, I have Vista and I'd like to increase my default buffering but it
only allows me to have a max of 60 seconds of buffering. Now my wireless
network is a 54mbps one which in theory should be plenty to stream a Divx
movie. But it's always, always a glitchy, start-stop video and is
unwatchable. I've moved my access point around and the reception is as max'd
out as it can get. Reckon if I can double by network buffer to 120 seconds
then all should be good, but of course rooting in the registry hasn't been
successful. So.... if anyone can help out, or offer some suggestions I would
be grateful. Worth adding I have searched for a solution already before
posting Thanks very much.