You have 3/16" standard inverted flare, standard sae fitting brake line. First thing you should do is inspect the rest of the brake line(s)...if one area is rusted out, chances are there is others that are not too far behind. Advance Auto or any other store has lines up to 72", some are even coated to prevent corrosion/rust. You can connect these with unions to the amount of length you need. Just make sure to measure before you go.
If you decide to replace the whole entire line, make sure to get the line specified above. Also, ford likes to use 1/4" fittings on the master cylinder and wheel cylinders. If working in these areas, make sure to grab a couple 3/16-to-1/4 adapters.
If you decide to only replace the area where its leaking, do it right...NEVER use compression fittings. Use a tubing nut, flare the line, and connect them together with a union. A flare tool can be had for under $30 bucks and is great to have in your tool collection. Always use caution when working on brake systems as you not only put yourself at risk, but other drivers around you...