Any auto parts store, lawnmower shop or motorcycle shop can supply you with fuel line. Look for 1/4" ID (inside diameter) and you'll be on your way. Small clamps are available but not really necessary. Nylon tie-wraps (zip-ties) will hold as well. Do not use aquarium or plastic tubing that is not compatible with gasoline. The kit supplied fuel line is notorious for premature deterioration (hardening) and should be replaced with something better.
Tom