Ihave dial up broadband from Orange which is a smartoucth modem connected via usb and telephone. Can I get a wireless router that will connect me to another computer upstairs
Yes. My example. Im with BT BB. Bought myself a D-Link wireless modem/router. Just install the router driver and the wireless driver and you are pretty much good to go.
Dont forget to set up an encryption code, they are unsecure out of the box.
You'll get plenty advice on setting up here, if needed.