The fluid is a mineral based fluid and is the same stuff that was used in the mid 1990's Citroen Hydrospastic suspension, you can buy a litre of the stuff from a motor factors for a fiver. Olives and the barbed fittings are available from pneumatics/Hydraulics suppliers such as Parker.
Syringes are available from chemists and the lengths of hose from a motors factors, windscreen washer hose.