Hi bes!
Welcome to the forum. Glad to have you aboard.
If you get a chance, please register your 'vert w/ vin # in the registry that we are building. It's one of the red sticky threads atop the forum.
As for your leak. It's difficult to say what you need to replace if we don't know which part is leaking. I would guess that a hose or hose connection might be the weakest link in that system, and most likely to be the cause of your problem. However, without some inspection, it's hard to know for sure.
Click on this link and then select the convertible supplement. Go ahead and download it and save it to your computer. It will be invaluable to you. There is a complete chapter on the hydrolic system with pictures and step by step instructions.
http://www.nicoclub.com/FSM/240sx/
Let us know if you have further questions and we'll help walk you through them. Hopefully we can avoid you having to spend much money.