Wireless routers and adapters are only made to work a certain range. There are some tricks you can use to get even better range from your home WiFi network. These include placement of your router and adapter, tweaking your router, and using long range antennas and higher power wireless adapters.
To get the best range from your home wireless Internet setup you should place the router as high as possible, such as on top of a bookshelf or in a windowsill. 802.11 G routers may transmit as far as half a mile. On your laptops end, consider using a USB based wireless adapter that has an external antenna. These can be found on eBay and by searching for "long range WiFi adapters." Using an outside antenna on your wireless router can double the range. Inexpensive magnetic mount WiFi antennas that feature the most common connection (RP-SMA) can be found for as little as $6.00. These accomplish the task of getting your wireless signal outside of the home and are particularly useful for connection sharing with a neighbor. Just keep in mind that as you extend the range of your WiFi network, others may be tempted to hack into it. Always choose the most secure method of securing your network with a password. For your SSID, or what you name your router, don't use your last name or address or the brand of router. Using the brand, such as Linksys, can help hackers know how best to compromise your network security.
On the "receiving end" or at the laptop or desktop where you want to pick up a distant wireless network, consider a high power adapter such as the Engenius - Senao series. Transmitting a full 600 milliwatts, about five times more than standard wireless adapters, they can lock into the distant WiFi signal better. In addition you can add a high gain omnidirectional antenna, or high gain directional antenna. You can find 2.4 Ghz WiFi panel antennas for sale on eBay and other sites. Some long range WiFi panel antennas conveniently contain an embedded WiFi adapter so all you have to do is plug them into your laptop or desktop and aim the antenna at the distant router. These are becoming increasingly common with people who live the RV lifestyle and must connect to weak RV park WiFi networks.
To establish an optimal long range WiFi network and get the most distance out of your home wireless Internet setup, or share your connection with a neighbor, you should optimize both ends of the system. Use a high gain antenna on the router, either a directional, panel antenna, or omnidirectional antenna mounted outside of the home. For the remote computer use a similar setup. Both directional antennas shold be aimed at each other.
In addition to the measures above you may be able to tweak your router's power settings. Since each router is different the procedure varies. Search Google for "tweak (insert brand of router) power settings." Normally this involves entering in the IP address of your router and entering "options," "settings," or "setup."
Keep in mind that adding high gain antennas to some routers may violate FCC rules. Check with the manufacturer of the router or wireless adapter and ask them what the maximum DB antenna is that can be used with their product.
How much range you get from your wireless Internet or WiFi network is dependent on many variables. These include what obstacles lie between your computer and the router, such as trees, walls, hills, etc. Under ideal circumstances, hobbyists in the Great Salt Lake established a 72 mile WiFi connection. Connections of over a mile can be easily obtained using directional antennas. Just follow the manufacturers instructions so as not to violate FCC rules.
To get the most distance from your home WiFi place the router as high as possible. Consider USB based long range adapters for more range. When increasing the range of your network always enable the highest security settings that your router allows. Never leave your home wireless network open, without a security key required.
For more on how high gain WiFi antennas work see: How Long Range Wireless Internet Antennas And Adapters Work