They stock 120w panels .. a pair of these will set you back about £1,400 ..
You will also need batteries .. I would recommend a pair of 100 AHr. from Mapin for about £350 ..
.. and I would also recommend some sort of motorised ’sun tracking’ system .. (sorry, can’t help there, however check out "eq mounts" as used in astronomy)
NB. your batteries will need to last overnight, so I assume you also need some sort of computerised power management system (to make sure you ‘ration’ your usage & don’t run out)
References :
http://www.maplin.co.uk/Module.aspx?ModuleNo=97380
http://www.maplin.co.uk/Module.aspx?ModuleNo=97389