Avid Shorty 4 Carbon Brake Pads
Assuming your current pads are V-brake style, these pads should work well: http://www.swissstop.com/rimbrakes/rxplus/yellowking/

As for the pad holders, it's not easy to find them sold without pads, nor with carbon pads.  That's too bad, but you can buy these anyway and use the pads on another bike: http://www.koolstop.com/english/v_type2holder.html