my internet source upstairs is my parent's router i have my own router in the basement connected to my computer etc for media streaming/ network sharing to my hardwired equipment, what im trying to do is use my computer to share the internet through a router while retaining the ability to stream through the network.
What is your router make and model for both your parents and yourself?
Basically, I'm thinking you could use DD-WRT on your router. You can use the software installed onto certain routers, it will allow you to use it as a wireless bridge, linking your router straight to your parents router, then all of your devices are on the same network. This way, you can maintain the connection whether your PC is on or not.
In relation to what you are specifically asking. Your PC is going to be doing the routing function.
Are you trying to stream from storage that is located on your parents network or are you just connecting to the internet?
1. Go to your wireless network connection on your PC
Go to advanced
go to sharing tick the box and select the wired interface to share with
2. Find the IP address that your PC has automatically assigned to the LAN interface.
3. Go to your router
change the DHCP address range to the same as your wired interface from step 2. Example, the PC wired connection may give you the 192.168.137.x address.
Go to the DHCP settings on the router and set the DHCP LAN address range to 192.168.137.0 subnet 255.255.255.0.
4. Reserve the IP address of your PC so that it doesnt assign it to another device
5. Plug your PC into one of the LAN ports of the router, not the WAN/internet port.
You should be good to go with that, however, I can't remember whether windows will let you share to devices that are on another subnet, but you can test.
My recommendation would be to use DD-WRT because it is significantly simpler, as you would not have any separation between the 2 networks and the performance of the network should be greatly increased. Also, even if your router is not compatible, you will find routers that it will work with for around a tenner or $15-$20 on ebay.