Larger rear brakes

[fatlapit]

Before i start i would like say i dont want to hear about why would i like bigger brakes on the rear. I would like to know if it can be done at a reasonable cost.

So my rear brakes are struggling.
current set up is: 
Standard calipers
ds2500 pads
wavy discs 
Extra cooling from ducts.

So ive done a few track days and my rear discs are blue. Only done croft and castle coombe. I believe my rear brakes are not man enough.

So what are my options to make the brakes bigger?

Bigger bells and rotors with a bracket to use my standard calliper.

Or

A totally new set up with 2 pots from willwood etc with bells rotors and bracketry?

Any relevant comments welcome