you wont need hub convertors, you could remove your hubs and have a machine shop drill the new stud pattern into your hubs, you would also need the brake discs done to suit too.

so when finished your hubs will have the standard stud pattern and also the stud pattern to match the new wheels, meaning the hubs will now have 8 holes in them.

all the above is assuming the focus wheels are 4 stud and not 5 stud