Lead generation and closing agency

We want to run campaigns on Facebook. Currently, we are getting leads at 25 Rs/lead with 2.87% conversion by calling people individually. We use adespresso to optimize our campaigns. What we are mainly looking for is to bring down lead rates to 15 Rs/lead. Improve conversion rate to 5%. We want to optimize this process by actually not calling all the leads but engaging these leads over *Removed by Admin* or any other channel you would like to suggest. Finally, call those who are seriously interested. This will set the process for us. Our current email template is something you will have to review. We can't give this project to amateur agency. You must have a great deal of experience to handle this project. We have several other projects if you get us desired results. We are open to discuss if you would like to suggest any alternative channels than FB. Please note, we don't need an agency which can get us leads only but manage the sales process as well because we are already getting ample needs but at higher costs and we need to do vigorously do the calling.