Please provide more details on your wireless and the computers. For example, do you have a wireless NAT router? Do you have a wireless and a NIC interface on the first computer? What kind of network interface do you have on your laptop?
If you have a wireless NAT router, but the laptop doesn't have wireless, then you can connect the computers via an ethernet cable (via switch or cross-over cable) and enable forwarding. In this situation you want the two computers on different subnets. If you want to share a wireless connection (and internet IP address), and don't have a NAT router, then you need to configure the firewall to perform the network address translation (NAT) in the first computer.