I had a look last week, but diden't find any GPU mining software for Primecoin. There are some drafts, but none is working? At least not on linux. Correct me, if I am wrong.
ASIC = special Hardware for mining maybe will never show up, Primecoin has not yet enought value to make special hardware for it.
So for mining primecoin in the moment you can just use your CPU. I have 3 workers on ypoo.net and I get ~0.5 XMP a day.