The router can handle both 802.11g (theoretical maximum of 54Mbps) and 802.11b (theoretical maximum of 11Mbps)...it sounds like you are using the latter instead of the former. First, check your laptop's specs and find out if it is capable of handling 802.11g...if not, there's your problem. The resolution would be to purchase a wireless networking card for it that does support the newer standard/faster speed. If the laptop is capable, check the router settings and see if it's utilizing just 802.11b...if so, you'll need to enable 802.11g as well.
Hope this helps,
Two days ago we bought a Linksys Router Model WRT54G and since installation the maximun speed in our laptop is 11 Mbps.
We live in a two stories well built house, the DSL and the router are in the second floor next to our table PC. We use our laptop in the first floor.
We tried changing the router channels, moving the laptop around the first floor of the house but so far no use.
We would appreciate very much, any suggestions about how to improve the speed on our laptop.