I would like to be able to use my surround sound speakers whilst watching normal t.v and sky, how do I do it.

Really depends on what surround system you have.
The one I have has various inputs so I have separate ones for DVD. Sky, games etc..

Its an lg 3d cinema system. Will I need extra leads.

Please provide the make and model numbers of your equipment and I will provide you the best way to connect your equipment.