Its about 500% easier to access the Mac from the PC. The Mac is all setup basically. All you have to do on the Mac side is go to System Preferences and then to Sharing. Check the Windows File Sharing checkbox and thats it.
Then on the PC side just right click on My Computer and select map network drive. Put in //nameofmac/username if what you want is on your desktop on the Mac. (ex. //imac/joeuser) When it prompts you for the password make sure you use the username and password for the Mac side, not the PC side. If you want to map the whole HD put in this:
//nameofmac/volumes/volumename Usually its just easiest to put everything you need on the desktop of your Mac. If your HD name has spaces in it, that may create problems. When it prompts you for the password make sure you use the username and password for the Mac side, not the PC side.
I'm assuming that the wireless network works on both platforms for the above to work. If not then you need to get the wireless working on both sides. The Mac side should be a piece of cake.