Accord Man... You have a router dont you... That is what will have you public address from the ISP. If you anything like me you never shut it off. Which mean that will keep the same address in a DHCP enviroment. Your router will then assign you a Private DHCP address because it is doing NAT. But like I said before chances are your router wont grab a new DHCP address because itll just keep renewing with the same one. Chances are your ISP will just tell you that its DHCP and your probably SOL unless you can get it to grab a new address. I doubt they will assign you a static address..
If you dont mind... Why is this such a big deal?