Yeh, you need a few more things - usefully all of which are available from Halfords. Incidentially, I work there so if someone at your local store tells you something that you're not sure about PM me, they're probably talking poo

Anyway, all you need is an amp wiring kit - in Halfords they're located with the rest of the audio connectors and wiring. Basic ones cost around £25-£35 and contain full instructions - they usually have power cables, signal cable, speaker cable and fuses and fixings.
It's very easy to do, hardest thing is hiding the wiring - and for your type of music I'd probably go for a 12" sub with a modest amplifier of around 200 - 300 watts.
Hope this helps
