I have managed multi-million $ telemarketing campaigns in Asia-Pac two years ago, so my pricing is not current. The best results were using Australian CSRs. Since we were paying for the infrastructure and not just a body, we paid about US$20/hr. For Korea we had to hire a local company in Seoul. I priced a reputable call centre in India but didn't use them. They were asking for US$13-$14/hr but wanted to see a commitment for 15-20 CSRs before they would talk any more.
I can't understate the value of getting the scripts right and using an interface that allows for flexibility in the sequence of questions.