Working backwards, here:
Year One, among others, sells new studs. RH only, from what I could find. They also seemed to be the cheapest around, although with shipping to the Left Coast it might cost a little more. Less than $3/lug, though. There were some other sites that came up to - Google is your friend here. Just make sure the length, pitch, and dia. are correct.
Also, in reference to your second question, you will have better results with an arbor press - solid bar stock of a similar diameter will work, but be careful with that hammer! Slow and steady wins the race - don't try to get it out in one shot.
As for removal of the axle and rotor, if you have discs (which it sounds like you do, if you have rotors) then it may be necessary. If you can access the backside (head) of the studs, then you should be safe. Otherwise, removal may be required.
Hope this helps!