hi all bit of advice needed...

need a set of front brake discs they are 330mm by 28mm i bought them in a group buy off here about 3 years ago, i think its called the gran turismo brake set came with discs caliper and hoses and brackets want a new set of discs they are on what looks like a ally bell so could i buy just the disc or is it best to buy the whole lot????

if so what and where do i buy them from??
advice please

craig.