You will need to set up a proxy server on your PC, and then get the PS3 to connect to the net via the PC. So if your PC only has one ethernet port, buy a pci network adaptor and the PS3 connected to that using an ethernet cable.
Doubt it, I've not done it myself so cannot confirm if this works. Your PC already has access to the network, so all you are doing is letting the ps3 hitch a ride on the PC to access the net, so you wont have to do any port forwarding i dont think. try this guide: http://www.ps3news.com/forums/ps3-guides-tutorials/how-use-ps3-proxy-server-guide-99030.html
