Xbox 360 wireless adapter?

I recently bought an Xbox 360, and I don’t have broadband internet (or any internet for that matter) at my house. I would like to know if the Xbox 360 work well online, with wireless adapter on neighbors connection (unsecured), the connection reads 50-60% on my PSP (which I used to locate hot spots in my house), I was thinking that the Adaptor is better then the PSP wireless “picker up-er” so that on the Xbox it would be read 70-80%.