sure but that is complex and not really what this fourm is here to solve. google the following phrase...
internet connection sharing
ideally you want to get a firewall or something that can NAT your public ISP address if you have issues with your ISP and multiple MAC address on the WAN then just spoof the MAC address of your Windows PC on the firewall
so to help with your ASCII art picture...
ISP---(wire)----FIrewall---whatever,media,you,want----what,ever,os,you,want
vendors that make this are ...linksys dlink netgear smc ..etc....etc..


