low signal

[kxs]

Hi, I`ve recently bought ASUS WL-500G Premium router. The only problem I get is it`s poor signal. I am ubuntu linux user and use router on both desktop and laptop (of course there`s no problem on desktop as I use cable connection).
My laptop is ASUS A6JC-Q085. It has built-in intel wifi card (think that is ipw3945). I can connect to router with this card, but the signal is very low. Network Manager in ubuntu shows about 50-60% when I`m right in front of the router. Isn`t that weird? (I get sometimes a stronger signal from someone`s elses Access Point)
When I`m in the next room, just few meters away the signal falls down to about 20% or less and connection is down.
The sam situation is with or without the antenna attached. Isn`t that weird either? Shouldn`t the signal be stronger then?
What`s wrong? Is my router broken? Or is this because of my wifi card? I`ve tested it with another laptop (windows and also Intel wifi card built in) and the same laptop with Compex PCIMCIA card used instead of built0in Intel`s. All is the same. Signal is very low and connection drops when I`m in another room. Could anyone help me, please?

[Moody Blue]

Read this article, maybe you are in the same situation regarding the external antenna

http://www.xbitlabs.com/articles/other/display/asus-wl500g-premium_3.html

[kxs]

thanks for your response. that whas really quick and what`s better you were right :) my connection is now about 95-97% and about 75% in another room
yeah!

and by the way, the antenna should be connected to AUX or main? (look at the picture: http://www.xbitlabs.com/misc/picture/?src=/images/other/asus-wl500g-premium/image031.jpg&1=1)
what are the diferences? does it mean that I can attach there a second antenna?