Mine low-pressure PS hose was leaking also, and the seeping fluid was wicking down the length of the metal "fluid cooler" pipe that wraps around the front of the radiator, leaving it coated in black "goop" (combined fluid and road dust, etc.).

I had a little bit of seepage from the top end of the hose, but most of the mess turned out to be due to a loose clamp at the lower end (between the hose and the cooler pipe). You might try just tightening all of the clamps first.

If you decide you need to replace the hose - either get some generic hydraulic hose at an autoparts store, or possibly get it online (most of the online places sell a 1m length for about $20). You can find the inside diameter spec. on-line. Whatever you do, don't pay $41 or so at the dealer for the same 1m length of hose