Both PC’s have win7. PC 1 (laptop) has a large amount of files not worth waiting for to transfer on an external drive first. Right now I’m experimenting on transferring over the same network from the router, but only getting a weak 3MB/s but PC 1 is on wireless G (but the connection is excellent so there even should be more throughput?) PC 2 is a desktop with a wired connection to the router.
If I had a crossover cable would that be faster than relying on the router? Can I just use basic windows file sharing there or would something like FireFTP work faster?



3rd party File Transfer Protocol programs are much faster than Windows File Sharing which actually uses the same method but in a more secure way.
However using FTP through a modem can hurt performance compared to that of a crossover cable between two physically connected computers.
Set up a network in which one computer is host and the other, a client.
By removing the need for a modem you will improve speed and by using a 3rd party FTP program you are removing the need of security.
Filezilla is a good free FTP client which I reach speeds of up to 7MB/s using a modem and 2Gbps w/o to a similar file system such as NTFS.
Cable is always faster than wireless, try hard wiring your laptop to the router