If you have a telephone line it is best to get your broadband through any of the ISPs that service your area, such as BT, or Talk Talk.
I don't know if your pc is wifi enabled. If it is you will be able to connect to your home wifi wirelessly via the router which may be supplied by your ISP.
If it isn't wifi enabled you can buy a very small wifi adapter that plugs in to your usb port, or connect it by cable.
If you don't want to do that you can try a broadband dongle, it all depends what your 3G reception is like.
The first option is the fastest and most reliable (in most cases).