Fuel Line?
Fuel lines are pretty inexpensive - so get the highest quality you can find. You want one that is rated for diesel - and is protected (best case).
Take out the old one, empty your filter, clean the bowl out, change your in-line filter put in the new one, and then bleed the system until the new diesel is at your injectors.
Then take the old nasty, dirty diesel and dirt to the recycling place for oils and fuels...I used an old milk jug... This is a job you can do yourself - and a good one to get you acquainted with your fuel line and chain from the tank. I also recommend running the engine (at the dock) for a good while to ensure you have no air pockets, etc...
//sse