wireless router range

hey guys
iam not really into network but i bought an New LG Intel Centrino core 2 notebook with wireless function, my router which is being used primely on my desktop pc is supposed to provide a 15m range but some how sometimes the notebook wont even connect in range of 5m. since my router is provided by my ISP i called them, they told me it depends on material used in housing which may weaken the signal, can it be?
i even used my nokia Communicator 9500 which shows similar issue and it only connects in same range as notebook.
am thinking on buying a more powerful router but before i do i need to conform that i wont be having same problem after wards.
please give me some recommending, i just want a router which gives a minimum range of 15 meters or less without disconnection to share net with just one notebook.
right now i have Siemens SpeedStream 6520
http://subscriber.communications.sie...xx_picture.jpg
http://whirlpool.net.au/index.cfm?a=h_view&model_id=279

am thinking of buying this:
http://www.newegg.com/Product/Produc...82E16833124084
http://images10.newegg.com/NeweggIma...124-084-03.jpg

If you have something metallic such as a boiler,immersion tank, between you and the router it will block you,try moving the router higher,lower,to the left or right and see if that improves the signal.
I think steel reinforced concrete would be harder to penetrate than brick.

Assuming that the Speedstream router isn't actually faulty then getting the linksys router isn't likely to improve the situation unless your laptop supports 802.11n.

The range indoors for 802.11g devices should be around 25m depending on factors such as building materials, but also electrical noise and interference from other wireless networks. I've seen nothing to suggest that the Speedstream has a shorter range, and I'm pretty sure there would be pages and pages of protests if that were the case.

Remember that if the signal has to pass directly through a wall there are only a few centimetres of building material, but if it has to pass through the wall at a sharp angle then you could be talking about a few metres of material. In some cases moving the router further away from the laptop can reduce this angle and consequently improve reception.

If moving the router doesn't help you may be suffering from network interference - wireless network channels overlap with about 3 or 4 channels on either side. Try changing the channel your router operates on. Most routers operate in the centre of the available channels (5, 6 or 7) so shifting to channel 1 or channel 11 may give an improvement since there can be no networks below (C1) or above (C11). You will have to re-acquire the network on your laptop after doing this.

One extra tip for anyone setting network channels - turn off your router and check if your pc can see any networks. If it can see any you should also be able to tell what channels they are operating on - set your own channel to be as far away as possible from these.