there is this way to make a really good antena that can catch signals up to a mile, you do it with a Pringles (chips) cyllinder and wire some stuff around, you can look on the internet and there are dirrections.
i have 802.11b 11 mbps but i was going to buy a booster that upgrades to 802.11b at 22 mbps with even more range but its 60$ which is alot comparted to others i have seen. do u know a link to the pringles can i dea?
If you are trying to expand your signal without spending money you can try simple things like relocating the router or keeping metal objects and other electronics (like microwaves) away.
I don't believe in "Extender" devices anymore. I have been through quite a few and it is still easier and usually cheaper to just buy another access point and use it to extend your network.