As to your first question, I am guessing that both machines are already on a wireless network, for internet access, no?
You just need to figure out how to connect between the two. I'll let someone with more pc knowledge speak on how to set it up on the PC side but on the Mac side it is pretty simple.
Preferences > Sharing > Services:
[X] Widows Sharing turns on smb services
[X] Remote Login turns on SSH services
[X] FTP Access turns on FTP services
then on your...