Re: Turn my laptop into a router?
You can create a virtual network interface to go on top of your physical one, to give the illusion of two cards.
I don't know the details of WEP or WPA2, whether your hardware can support both protocols, but the idea is sound at least for entertainment or education.
What is NOT viable is to separate security between the two networks. The packets for both "networks" travel through the same space, and if they are routed by your laptop then those routed packets might be "secure" on the one side but not secure on the other, making your secure side no better than the less secure side.
So if your desire to not "downgrade" your router is for security reasons, your laptop router project will be the security hole you're afraid of, at least for the packets being routed and if your laptop can be compromised, the entire traffic can be had.
Help stamp out MBR partition tables. Use GPT instead!