You can use the wireless card already in your computer to strengthen your network and get others connected via the card's access point (AP) mode. AP mode is an option in the card's software that turns your wireless card into several types of wireless tools, such as a router and signal repeater, according to NETGEAR.
In AP mode, your wireless card allows others to connect to the Internet or a larger network by sending requests to your computer. Your adapter can also boost wireless signals to extend the range of your network.
As a true access point, AP mode cannot protect your computer as well as a normal router would. On a normal router, there are security features, such as wireless encryption, and all clients on the network can hide behind a single IP address. AP mode doesn't provide such protections.
In AP mode, other computers cannot talk directly to each other. They can only correlate through the host computer. If you just want to share an Internet connection between computers, you can use a similar mode called ad-hoc.