[DivByZero]

The best way would be to have access to Facebook Ads API. That would make everything really simple.

However keep in mind that you could only get a generail indication of the price through time for your given target. The real CPC Facebook apply to your ads change every minute and it's highly influenced by the quality of your ad.

The better your CTR is, the lower the CPC goes. Another factor that influence the CPC is how wide is your target. Usually targeting a small segment is more expensive than a broad target.

Anyhow, you can probably gather some useful data on CPC for your market from Optimal Social: http://www.optimalsocial.com/