Allright buddy.
not sure what the stock barrel is like but im sure its not the best.id start with a new barrel.dye,freak,shaft if you can afford it.
12v reveloution hopper, but if you have the extra cash go for an "evoloution II".loadz of them on these forums cheap.
20oz co2 bottles are about £20, but if u can afford it air is a better option.
small bottles cost u about £50-90.
that'd get u started off.