Cheapest= Greenstuff Pads
Most effective would be 4 pot calipers up front. The 2 pot brakes you have do work but you need to push hard as you know to stop promptly.
I had the 2 pots replaced with 4 pot Hi Spec brakes which are very good. £360 including pads and aeroquip hoses which expand less when you push the pedal. All from Mulfab who I can recommend. Unless good with a spanner you need to factor having them fitted. If you are in the Midlands Chas Windridge at Mogsport can fit them- he shares a workshop with Mulfab.
Mulfab details..
http://www.mulfab.co.uk/our-products/25/brakes/44-and-4If in the south Tim Ayres at New Elms good for fitting,
John
