Your laptop will have a 3.5 mm coax socket that outputs sound.  It has a smal, drwaing of a headset.  Route that threough your amp or buy some powered speakers at Radio Shack or Circuit City -a ssuming that you are in the US.  Or Maplins or PC World in the UK.   They can supply cables for amps as well.
                 Terry
                
 August 2006