Unless the wishbones and top links are really rusted, just a clean and repaint should be OK. All bushings can be had from Redline in the UK and relatively easy to replace using a press. Don’t bother trying without one. Great service and knowledge from Chris Mintoft.
http://www.redlinecomponents.co.uk/
They can supply springs and dampers although there are many options available either from Caterham or independent suppliers such as Redline, Merlin Motorsport, Gaz, Avo etc. Start with Chris if you want standard spec.