Sears sells a set that has every size you will ever need for $9. Thats where I got mine at. Very simple to do, push the tool up into the connector and push with the opposite line, pull the tool out and keep the pressure pushed on the oposite line, then just pull apart. Very simple should take you around 5 seconds to do.
Look in the A/C repair section for the fuel line tools. They look like little plastic top hats. You will need the 1/2" & 5/8" ones. The hat shaped section goes on facing the large part of the coupling. Then you press hard on the brim until it forces the sleeve into the coupling and releases the spring. You may need someone to pull on the line while you press on the coupling. Put some motor oil on them when you put the line back together.