I noticed some hydraulic fluid on the garage floor under the car and found these lines (in pics) are rotted.

The reservoir is still full and the spot on the floor is about 5" in diameter since lastnight. How tough is it to replace these and what else should I do while I'm at it (I was going to replace the accumulators). Does anyone know how much these lines cost? The rot in the photos is all I can find.
Which part numbers will I need? I'm not sure.
Russian Part Number Site
I've read that it won't destroy anything if I drive with a leak in the sytem. Is this true? Any help would be greatly appreciated.