You are using a single dynamic page with 250 phone numbers? Are you using a unique number per location?
My suggestion would be to use Google tracking numbers for websites that will assign a unique number each time a user visits the page through an ad, and then attributing the conversion to the campaign > ad group > keyword/banner.
More information is available here.
When you create the conversion within Google AdWords, it wll provide you with a custom script you can apply to your page(s).
Let me know if this helps?