I think what you are trying to do is almost impossible. You should be able to get internet access in all of the computers, but they will be in two different subnets (and therefore two different networks).
If Computers 1 (wired) and 2 (wireless) have internet access, you can connect PC3 to PC2 and enable Internet Connection Sharing on PC2's connection to the router. This will give PC2's Local Area Connection the IP address 192.168.0.1 and PC3 will get an IP address in the same subnet by DHCP from PC2. However, to avoid an IP conflict, the subnet that the router operates in must be different from the 192.168.0.0 subnet used by Internet Connection Sharing. The result of this is that PC1 and PC2 will communicate (both connected to the router), PC2 and PC3 will communicate (connected directly by crossover cable), but PC1 and PC3 will not communicate.
Now, if the router's subnet was, for example, 192.168.1.0 and you were able to change the Subnet Mask throughout all of the network devices from 255.255.255.0 to 255.255.0.0 then the two subnets should communicate. The problem is that doing this will almost certainly prevent ICS from functioning in PC2.