Do I understand correctly that you want to make your website on your local computer on the Internet?
Apart from the poor uptime that you will experience with this you will need a number of things:
1) Create a tunnel/ server address of your local computer on your Internet Router. This will also mean you will need a fixed IP address on your local network, not DHCP. Refer to your Router's documentation.
2) Set up a DNS record www.domain.com to your IP address, either your ISP gives you a fixed IP address or you need to use some Dynamic DNS provider.
3) Make sure that Apache listens to your local network IP address.
Ensure you are listening to Port 80 by having
Set up Virtual Hosts on your IP address,