Welcome to JustAnswer.com! My name is DriveFast71(Ron) and I will do my best to answer all of your questions completely and accurately.
On this vehicle, the Ball Joint is replaced by replacing the entire lower control arm (the ball joint is not sold or serviced seperately). The control arm with new ball joint sells for around $229 and the labor time guide calls for 1.2 hours to complete the job. Labor rates vary from shop to shop, so what you pay for labor will effect the botXXXXX XXXXXne. Keep in mind- after this type of front end repair, it's highly recommended that you also get a front-end alignment as well.
I don't exactly agree with the 4 new tires. I mean, if you see any sort of unusual wear (rub your hand along the face of the tire looking for any uneven wear or "feathering") then quite possibly, you need tires. However, if they still have good tread, and no wear- then I don't believe one faulty ball joint constitues 4 new tires.
Ahhh. ok. Then yes, this is the BEST time to get the tires and work done. Have the ball joint replaced, then the tires put on and THEN the front end alignment. This will ensure everything wears in evenly.
Unfortunately, yes- it's actually quite common for front end parts to wear this early, especially since you do a lot of long distance driving.