Wifi really slow in Ubuntu

I just switch to Ubuntu and miracle, I finally managed to have a connection without a penny (before I was on Debian and impossible to set my wifi).

So far so good, but my wifi is very slow and its scope is really poor, I can not go in my room which is on the floor while it works perfectly under Vista and other wireless equipment.

To avoid unnecessary long code, I copied in a pastebin

http://pastebin.com/f767fc90c

I'd like to know where the problem and be able to adjust more quickly, I'm Ethernet at this time.

Thank you.

Me precisely the opposite, my laptop detects the best wifi in ubuntu (9.04) that under vista, it must surely depend on the model.

Try this:

Code:

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iwconfig wlan0 rate 54M

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See also if you can increase your power output

Thank you for your response, I tried the command and no change.