Setting up WL300g to boost wireless signal

Hello,

I recently moved to a new house in a city that has a citywide wireless network (www.wirelessleiden.nl). As I'm still waiting for my ADSL connection to come through I tried this out and found that I could use this network if I place my laptop against the window. If possible I would like to use my wl300g, with the WL300g-1.9.2.7-6b.trx firmware, to catch this signal and boost it so that I can sit on the couch with my laptop.

How would I go about doing this?

Thanks a bunch

Unless wirelessleiden supports WDS you probably want to use OpenWRT and set your wl300g in client mode.
As for the boosting you will need a second AP connected to your wl300g